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Papers - Yan, Jiwang

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Micromachining of Carbon Fiber Reinforced Plastics Using Femtosecond Pulsed Laser

Konishi, Y; Yan, JW

NANOMANUFACTURING AND METROLOGY 8 ( 1 ) 2025.12

ISSN 2520-811X

Microscale grooves and holes were fabricated in carbon fiber reinforced plastics (CFRPs) using femtosecond pulsed laser irradiation, and the characteristics and mechanisms of laser processing were investigated. The relationship between laser fluence and ablation depth was established by measuring the cross-sectional profiles of the microgrooves produced at different laser fluences. Furthermore, the effect of the angle between the edge of the micro holes and the carbon fibers was examined by analyzing the edges and wall surfaces of circular and rectangular holes. Experimental results revealed that the laser processing mechanism was strongly dependent on fiber orientation due to significant heat conduction along carbon fibers. The findings of this study contribute to a deeper understanding of the ultrashort pulsed laser processing characteristics and mechanisms for creating small holes in CFRPs and emphasize the possibility of drilling high-precision holes that can be used in the direct bonding of sensors/IC chips to CFRPs.

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Effect of System Dynamics on Surface Topography in Fast Tool Servo-Based Diamond Turning of Microlens Arrays

Hashimoto T., Yan J.

Nanomanufacturing and Metrology 8 ( 1 ) 2025.12

ISSN 2520811X

A lens array is often used for optical components of sensing devices, requiring high surface quality and form accuracy. Fast tool servo (FTS)-based diamond turning is one of the technologies for manufacturing complicated shapes, such as freeform optics, structured surfaces, and microlens arrays, with high machining efficiency. In this study, lens array machining was performed on copper using an FTS on a diamond turning machine. For evaluating the lens array surface topography, the focus was on surface waviness formation. As a dominating factor of surface waviness, the system dynamics behavior was investigated by capturing and analyzing the position signal. It was found that a specific waviness pattern could be formed on the surface due to the servo response. By considering the dynamics of the FTS system from the captured signals, the FTS system behavior was identified, and optimal machining parameters for the lens array were proposed. A machining test under the optimized cutting conditions reduced the average Sdq used to quantify the waviness amount from 93 to 50 µrad and the standard deviation from 33 to 3 µrad, which greatly improved the consistency in accuracy for all lens arrays. This study will contribute to the appropriate utilization of FTS systems in the ultraprecision machining of various advanced optics, such as microlens arrays.

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Fabrication of Groove-with-Protrusion Surface Structures on Oxygen-Free Copper Using a Laser-Engineered Burnishing Tool

Otani A., Yan J.

Nanomanufacturing and Metrology 8 ( 1 ) 2025.12

ISSN 2520811X

Microtextured surfaces, such as those with groove, hole, or protrusion structures, are widely used in various industries for bonding dissimilar materials because of their anchor effect, which enhances adhesion and penetration with other materials. Although surfaces with grooves and protrusions are expected to show higher bonding strength, it is difficult to fabricate such hybrid structures using a material removal process or additive manufacturing. This study established a new burnishing method using a tool with preformed microgrooves at the tip to fabricate groove-with-protrusion structures on metal surfaces by plastic deformation. The tip of a ball-shaped polycrystalline diamond (PCD) tool was irradiated with a femtosecond pulsed laser to generate multiple trapezoid ten-micron scale grooves. Burnishing was then conducted on an oxygen-free copper surface to investigate the characteristics and mechanism of the burnishing-induced plastic deformation behaviors. The results showed that protrusions and grooves, which were several tens of micrometers in height and depth, were simultaneously produced along the tool path on the material surface. Tool sliding on the workpiece induced shear stress, which mainly triggered dislocation movement and plastic deformation enhancement. Cross-sectional observation revealed that grain elongation and refinement remarkably increased with the burnishing depth, indicating that the shear stress from burnishing produced refined grains that flowed and formed the protrusions. This research demonstrates the feasibility of a highly efficient method for simultaneously generating groove-with-protrusion structures with enhanced surface properties.

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Amorphization of pure aluminium in ultraprecision cutting process: experimental observation and theoretical analysis

He C., Wang S., Yan J.

CIRP Journal of Manufacturing Science and Technology 60 76 - 87 2025.09

ISSN 17555817

Preparing amorphous pure metals has long been significantly challenging because of their stringent transformation requirements. Here, we report a surprising discovery: the preparation of a layer of amorphous aluminium by ultraprecision cutting a polycrystalline bulk material. The findings indicated that under specific cutting conditions, polycrystalline aluminium was transformed into a completely amorphous phase on the surface layer. Additionally, the material matrix exhibited shear bands, including an amorphous phase, a 9 R phase, and high-density SFs. The modification resulted in a significant increase in surface micro-hardness, with the average value increasing from 0.93 ± 0.13 GPa to 2.21 ± 0.92 GPa. The amorphization in the ultraprecision cutting process is attributed to the high shear strain and strain rate, as confirmed by molecular dynamics simulation and theoretical calculation. This study provides a novel approach for preparing an amorphous layer on a crystalline aluminium bulk material to enhance its surface properties.

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Micro-convex structure-assisted laser-induced backside dry etching for high-efficiency fabrication of micro-groove array on fused silica toward manipulation of wetting characteristics

Huang H., An H., Qian Y., Zhang Z., Jiang M., Yan J.

Journal of Manufacturing Processes 145 236 - 251 2025.07

ISSN 15266125

Fused silica has garnered significant attention in various industrial applications. The creation of surface micro/nanostructures on fused silica can impart specialized functional properties, such as extreme wettability, ultra-high transmittance, and excellent antimicrobial characteristics. Nonetheless, existing technologies for achieving surface micro/nanopatterning of fused silica, including wire electrical discharge machining, chemical etching, and electrochemical deposition, generally suffer from long processing cycles and high energy consumption, which are inconsistent with the development concept of the low-carbon economy. In this study, a novel approach termed micro-convex structure-assisted laser-induced backside dry etching (MCSALIBDE) is proposed for high-efficiency fabrication of micro-groove array on fused silica surfaces. The synergistic effect of enhanced heat conduction and plasma explosion in a confined space facilitates material ablation. The impact of processing parameters including scanning pitch and peak laser power intensity on the morphological and topographical features of the MCSALIBDE-processed fused silica surfaces is studied. Notably, the micro-groove structures with a depth-to-width ratio of 1.19 is fabricated. Furthermore, the wetting behaviors of the MCSALIBDE-processed fused silica surfaces before and after annealing treatment are studied. Experimental findings reveal that the MCSALIBDE-processed fused silica surfaces exhibit enhanced hydrophilicity compared to the untreated one. After annealing treatment, a transformation from hydrophilicity to superhydrophobicity is observed. The superhydrophobic surfaces produced under different laser parameters exhibit distinct adhesion and droplet bouncing behaviors. This work offers an in-depth understanding of the high-efficiency fabrication of micro/nanostructures on fused silica surfaces and as well the modulation of their wetting characteristics, heralding innovations in surface engineering for diverse applications.

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Micro-amplitude vibration-assisted scratching: a new method for one step and controllable fabrication of the microscale V-groove and nanoscale ripples

Wu H., Huang H., Zhang Z., Yan J.

International Journal of Extreme Manufacturing 7 ( 3 ) 2025.06

ISSN 26318644

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Unveiling the effects of laser scanning direction and processing parameters on heat transfer and ablation behavior of CFRP

An H., Qian Y., Jiang M., Huang H., Yan J.

Composites Part B: Engineering 298 2025.06

ISSN 13598368

Carbon fiber reinforced plastic (CFRP) has found extensive applications in aerospace, automotive, and biomedical fields owing to its exceptional mechanical properties. Nanosecond pulsed laser processing offers a promising avenue for treating CFRP laminates; however, the inevitable thermal damage during processing may significantly degrade the surface integrity. An in-depth analysis of the correlation between ablation characteristics of CFRP and laser processing conditions is essential for understanding the complex heat transfer and ablation mechanisms during laser processing of CFRP and is a prerequisite for improved control of thermal damage. This study examines the thermal transfer and ablation behavior of CFRP subjected to nanosecond laser ablation, focusing on how laser scanning direction and processing parameters influence the surface characteristics of the laser-ablated regions. The results indicate that the width of the heat-affected zone (HAZ) increases with increasing laser power, decreasing scanning speed, and decreasing scanning pitch. Moreover, the scanning direction plays a crucial role in determining the HAZ characteristics and material removal rate. Processing CFRP along the 0° direction relative to the carbon fiber orientation yields higher efficiency and less thermal damage compared to the 90° direction. Chemical composition analysis reveals that laser ablation induces a structural transformation in carbon fibers, shifting from sp2 graphite-like lattice orbitals to sp3 hybird orbitals. Numerical simulations further elucidate the heat transfer and ablation mechanisms under various experimental conditions. This study contributes to a deeper understanding of the laser-CFRP interaction, facilitating the development of high-integrity CFRP surfaces and broadening their practical applications across multiple industries.

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Investigation of the Effect of Tool Rotation Rate in EDM Drilling of Ultrafine Grain Tungsten Carbide Using Predictive Machine Learning

Gattu S.D., Bernardi L.P., Yan J.

Journal of Manufacturing and Materials Processing 9 ( 6 ) 2025.06

Electric discharge machining (EDM) is widely employed for machining hard, conductive materials. Tool rotation has emerged as an effective strategy to enhance debris flushing and improve stability during deep-hole EDM drilling. This study proposes a machine learning-based approach to evaluate the influence of tool rotation and predict the unstable machining conditions in EDM of ultrafine grained tungsten carbide. A structured analytical workflow, combining Taguchi–Grey optimization, regression analysis, and classification models, was designed to capture discharge dynamics across macro- and micro-timescales. Classification models trained on raw and processed electrical signal features achieved over 88% accuracy and 90% recall. SHAP analysis revealed that the relationship between key discharge events such as sparks and short circuits varied significantly across stable and unstable machining phases, underscoring the importance of phase-specific modeling. While correlation analysis showed weak global associations, phase-dependent SHAP values revealed opposing feature effects, allowing the context-informed interpretation of model behavior. Phase segmentation revealed that, compared to 1000 RPM, short circuits were reduced by about 40% during stable machining at 8000–9000 RPM. Conversely, during unstable phases, spark effectiveness dropped by nearly 45%, and secondary discharges increased throughout this range. These insights support the design of adaptive control strategies that adjust the rotation rate in response to detected phase changes, aiming to sustain machining stability. The findings support the development of dynamic control frameworks to improve EDM performance, particularly for mold fabrication using tungsten carbide.

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Time delay compensation in high-speed diamond turning of freeform surface using independent fast tool servo with a long stroke

Hashimoto T., Yan J.

Precision Engineering 93 515 - 527 2025.05

ISSN 01416359

The demand for wearable device applications has continuously grown in recent years, especially with the significant rise of augmented and virtual reality technologies. Freeform optics plays a crucial role in these devices by enhancing optical performance, shortening the light path, and reducing the weight, all while allowing for smaller, lighter systems with higher efficiency. The independent fast tool servo (FTS)-based diamond-turning method stands out as a highly effective technique for fabricating freeform shapes with high accuracy and productivity. However, microsecond-order time delays occur within the system, significantly impacting form accuracy as machining speeds increase. This study explores the sources of form errors in freeform surface fabrication associated with the FTS diamond-turning process, with particular attention to the effects of clocking angle errors caused by the time delay. These errors were found to greatly affect form accuracy, especially at higher machining speeds. The FTS position data were analyzed, and time delays under various operational conditions due to servo control were confirmed. To precisely identify the extent of the time delay, a cylindrical surface was machined under high-speed conditions, and the clocking angle error was measured using a non-contact chromatic probe. Results showed that time delays originating from the machine platform had a significant effect on form accuracy. By accurately identifying and compensating for these time delays, the clocking angle error was eliminated. To validate the effectiveness of the time-delay compensation strategy, a cylindrical freeform surface was machined after the compensation, and the clocking angle error was minimized down to 0.00014° evaluated by on-machine measurement. The form accuracy of the freeform machining result after compensation was achieved at 0.85 μm PV. This study establishes a methodology for identifying and compensating for time delays in an independent FTS system, contributing to improved form accuracy in freeform optics fabrication.

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Evolution of surface and subsurface properties of Zr-4 alloy under the combined effects of laser heat treatment and laser gas nitriding: Microscopic morphology, chemical composition, and mechanical behavior

Xu P., Qian Y., An H., Guo H., Zhang Z., Jiang M., Huang H., Yan J.

Journal of Materials Processing Technology 339 2025.03

ISSN 09240136

Zr-4 alloy, extensively employed as cladding in nuclear reactor fuel rods, stands as the foremost line of defense for reactor safety. Given its susceptibility to defects such as micro-pores during casting and its long-term exposure to extreme conditions during practical service processes, enhancing the surface and subsurface properties of Zr-4 alloy is essential. Herein, a nanosecond pulsed laser is used to irradiate the Zr-4 alloy in a nitrogen environment to investigate the evolution of its surface and subsurface properties under the combined effects of laser heat treatment and laser gas nitriding. The experimental results reveal a remarkable augmentation in surface hardness and scratch resistance of the Zr-4 alloy after laser irradiation. Notably, the hardness of the laser-irradiated surface obtained with a laser power of 23.0 W and a scanning speed of 150 mm/s reaches 19.10 GPa, which is more than 7 times higher than that of the untreated surface (2.37 GPa). These improvements are attributed to the synergistic effects of the introduction of hard ZrN phase, the reduction of subsurface porosity, and grain refinement. This study demonstrates a promising approach for significantly improving the mechanical properties of Zr-4 alloy, holding considerable practical significance for its applications in the nuclear energy industry and other relevant fields.

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Coupled SPH-FEM Simulation Model to Analyze the Mechanism of Single Particle Impact in Abrasive Waterjet Machining

Abdelhameed Y., Maher I., Yan J., El-Hofy H., Hassan M.A.

Tribology in Industry 47 ( 1 ) 77 - 91 2025.03

ISSN 03548996

Studying single particle impact is crucial to understanding the erosion mechanism in abrasive waterjet machining (AWJM). In this paper, the finite element method (FEM) and smoothed particle hydrodynamics (SPH) were combined to investigate the mechanism of single particle impact under the waterjet influence. The particle (garnet) and workpiece (Al 7075-T6) were represented by FEM, while the waterjet was discretized using SPH. Linear elasticity and the Johnson-Cook (JC) model were selected to model the abrasive and workpiece materials, respectively. The simulation was conducted in ABAQUS where the effects of particle shape, position, and impact angle on material removal were investigated. The results of the developed model revealed that the erosion mechanism and mechanics significantly differed when considering the waterjet effect. This was primarily attributed to the dynamic phenomena resulting from the waterjet impact, including stagnation zone and drag forces. It was found that the impact angle corresponding to maximum erosion depended on the particle shape and radial position within the jet stream. The presented model has proved its capability since it offers a novel perspective on the single particle impact mechanism by incorporating the realistic dynamic phenomena accompanying the impact in AWJM.

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Fabrication of microcone arrays on Ti6Al4V by nanosecond laser nitriding

Zhang H., Wang B., Yang Z., Zhang H., Zhang Z., Huang H., Yan J.

International Journal of Mechanical Sciences 287 2025.02

ISSN 00207403

The application of titanium alloys still faces some challenges such as relatively low hardness and insufficient wear resistance. Nanosecond pulsed laser irradiation in a nitrogen atmosphere has proven to be effective for fabricating micro/nano structures on titanium alloys, enhancing surface hardness and wear resistance. However, micro/nano structures produced by line-by-line laser scanning often exhibit directional differences and surface defects such as re-deposited particles and pores. Herein, vertically crossed laser scanning in a nitrogen atmosphere was employed to address the directional difference, enabling the simultaneous fabrication of microcone arrays and nitriding layers on Ti6Al4V surface. To eliminate the surface defects on the microcone structure, laser surface finishing via defocused scanning was performed, followed by morphological analysis, bonding force evaluation, and tribological performance testing. The results showed that the area percentage of re-deposited particles on the laser-finished microcone array surface decreased from 24 % to 5 %. The bonding force of the nitriding layer was assessed using linear loading scratch tests, and the highest value of 69 N was obtained. To investigate the wear resistance of the laser-finished microcone array surface, friction and wear tests were performed. From 25 °C to 600 °C, nearly no wear grooves were observed on the tested surfaces, demonstrating excellent high-temperature wear resistance. The wear mechanism was mainly related to the cutting action of the microcone structures on the counterpart ball. This study advances the fabrication of micro/nano structures and simultaneous nitriding on titanium alloys, demonstrating the significant potential for practical applications as surface contact materials.

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Nanoindentation behavior of the laser-repaired CoCrFeNiV high-entropy alloy

Wang C., Huang W., Yi C., Jiang M., Huang H., Yan J.

Intermetallics 177 2025.02

ISSN 09669795

High-entropy alloys (HEAs) are solid-solution alloys composed of multiple elements, exhibiting excellent mechanical properties. The unique plastic deformation mechanism induced by their specific solid solution structures has attracted considerable attention but remains incompletely understood, particularly at the micro-scale. In this study, the surface morphology, chemical composition, and microstructures of CoCrFeNiV HEA before and after laser remelting repair were investigated. Nanoindentation testing was employed to characterize the surface hardness and creep behavior of the repaired surface. The distribution of surface hardness before and after laser remelting, as well as the indentation creep behavior under different loads, were studied. The mechanism of indentation creep on the repaired surface was discussed and analyzed. The effect of microstructures of HEAs, including precipitated phases and sub-grain boundaries, on dislocation-dominated micro-scale plastic deformation was elucidated by the transmission electron microscope (TEM). This study contributes to an in-depth understanding of the creep behavior and micro-scale deformation mechanisms in HEAs.

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Special Issue: The State-of-the-Art in Japanese Manufacturing Research

Kakinuma, Y; Matsubara, A; Matsumura, T; Sugita, N; Suzuki, N; Takahashi, S; Yan, JW

JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME 147 ( 1 ) 2025.01

ISSN 1087-1357

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Femtosecond Pulsed Laser Machining of Fused Silica for Micro-Cavities With Sharp Corners

Brinkmann, M; Qian, YF; Huang, H; Yan, JW

JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME 147 ( 1 ) 2025.01

ISSN 1087-1357

Fused silica is an important material for applications requiring high temperature resistance, low thermal expansion coefficient, and excellent optical properties. The machining of micro-cavities on fused silica surfaces is of particular interest for micro-fluidic manipulation and miniaturization of high-quality optical waveguides, etc., but it still remains technically challenging for traditional manufacturing techniques. In the present study, machining of square cornered semienclosed micro-cavities on fused silica surfaces by femtosecond laser has been investigated experimentally. The effects of laser machining conditions including laser power, laser scanning speed, laser incidence angle, and laser-off delay time on the sidewall slope and bottom surface roughness of the micro-cavities were comprehensively investigated. The results indicated that laser power played an important role in determining the sidewall slope of the micro-cavity, while the laser scanning speed had a significant influence on the bottom surface roughness and subsurface damage. Furthermore, the sidewall slope of the micro-cavity was linearly increased as the laser incidence angle increases. By using a laser incidence angle of 10 deg and a laser-off delay time of 280 ms, a micro-cavity with sidewall slopes close to right angles (90 deg) was fabricated. This study demonstrates that femtosecond laser machining is an effective method for fabricating sharp cornered micro-cavities in fused silica, and the appropriate selection of laser machining conditions based on practical application scenarios is important.

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Subsurface amorphization-induced ultrasmooth and ultrahard surface during the diamond turning of polycrystalline pure copper

Wang S., He C., Wang Z., Yan J.

Materials and Design 249 2025.01

ISSN 02641275

Previous simulations indicated that pure metals can be amorphized during diamond turning. However, no pure metal has been successfully amorphized during this procedure to date. Herein, a comprehensive study on the surface formation mechanism was performed by examining the surface finish and subsurface variation characteristics. Polycrystalline pure copper was selected as the working material. In this study, the amorphization phenomenon and lattice structure transformations (from face-centred cubic to hexagonal close-packed and monoclinic structures) of pure copper were observed. The amorphization and phase transformation inside the working material depended on the tool nose radius being large, the cutting edge being sharp, and the feed rate being low. By using a large-nose-radius (10 mm) diamond tool with a sharp cutting edge (10.3 nm) at a low feed rate (0.5 μm/rev), an ultrasmooth and ultrahard surface with a 0.61 nm roughness Sa and 5.0 GPa nanohardness was achieved. Molecular dynamics simulations revealed that the high shear strain was responsible for the amorphization and lattice structure transformation during pure copper diamond turning. The findings of this study were considered critical for generating an amorphous subsurface layer in a pure metal and for achieving a ultrasmooth and ultrahard surface using single-point diamond turning.

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Nanosecond Laser Nanopatterning of Highly Ordered Nanodot Arrays on Silicon Surface: Breaking the Monopoly of Femtosecond Lasers

Qian Y., An X., An H., Huang H., Geng Y., Zhang Z., Huang W., Yan J.

Laser and Photonics Reviews 19 ( 11 ) 2025

ISSN 18638880

Laser nanopatterning is an effective strategy to manipulate the surface properties of materials. One of the glaring restrictions is that the fabrication of long-range ordered nanostructures typically relies on ultrafast lasers, especially femtosecond lasers, while the insurmountable thermal effects associated with the longer pulse durations of nanosecond lasers are deeply considered to be the nemesis of this scenario. Herein, for the first time, a nanosecond laser-based nanopatterning technique for fabricating highly ordered nanodot arrays on the monocrystalline silicon surface through a remarkably straightforward process is proposed. The mechanism involves Marangoni flow-assisted low-threshold oxidation of monocrystalline silicon induced by nanosecond laser, along with a domino-like growth process of nanodots driven by optical near-field enhancement. Finite-difference-time-domain (FDTD) simulations provide insight into the underlying origin of nanosecond laser-induced nanodot arrays. The prepared large-area nanodot arrays demonstrate a range of functionalities, including the manipulation of light reflection and diffraction, structural color, and surface-enhanced Raman scattering (SERS). The present study challenges the established view that the pronounced thermal effects associated with the long pulse durations of nanosecond lasers are incompatible with high-precision nanopatterning, which opens new avenues for research into laser-matter interactions.

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Statistical modeling and optimization of ultrasonic vibration assisted end grinding of alumina ceramics

Mansour M.M., Maher I., Nassef M.G.A., El-Hofy H., Yan J., Khairaldien W.M.

International Journal on Interactive Design and Manufacturing 2025

ISSN 19552513

Alumina is an advanced ceramic material that has numerous applications in dentistry and medicine. Ultrasonic-assisted end grinding proved to be one of the most successful and efficient ceramic processing techniques. However, the current state of the art in UAEG of alumina is mostly limited to finishing operations with low material removal rates. In this paper, UAEG is investigated to find the optimum grinding conditions of roughing operations of alumina ceramics. Response Surface Methodology was employed to study all combined effects of the spindle speed, feed rate, depth of cut, and vibration amplitude on the MRR, grinding forces and surface roughness. The surface morphology of the ground surface and the magnitude of the resultant grinding forces were recorded and analyzed for each test. The results showed that the vibration amplitude has the most influential effect on surface roughness with a contribution of 32.08%, while the grinding force is most affected by depth of cut (32.02%). The spindle speed of 9500 rpm, feed rate of 900 mm/min, depth of cut of 47 µm, and vibration amplitude of 2.6 µm are found to be the optimum machining parameters that maximize MRR and minimizing the grinding force and surface roughness.

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Surface finishing by shape-adaptive processes

Yan J., Mullany B., Beaucamp A., Meyer D., Sugita N.

CIRP Annals 74 ( 2 ) 1019 - 1045 2025

ISSN 00078506

Complex surfaces are increasingly used in optics, biomedical devices, and aerospace industries. Additive manufacturing and five-axis milling can produce complex shapes, but additional finishing processes are needed to meet the surface quality demands. This keynote paper reviews shape-adaptive finishing processes that enable uniform surface quality improvement without altering the shape. Key factors affecting shape adaptability, processing efficiency, and material applicability are analyzed and optimal process selection strategies for finishing complex surfaces are discussed. Future possibilities and research topics in this area, including process modeling/simulation, digital twin, surface/subsurface metrology, functionality evaluation, and applications of advanced robotics and artificial intelligence, are outlined.

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Finite element analysis of material removal in AWJM using different material models and spatial distributions for garnet abrasives

Abdelhameed Y., Maher I., Yan J., El-Hofy H., Hassan M.A.

International Journal of Machining and Machinability of Materials 27 ( 2 ) 121 - 144 2025

ISSN 17485711

Garnet, the most widely used abrasive material in abrasive waterjet machining (AWJM), presents challenges in modelling its behaviour. Therefore, a finite element (FE) model was proposed to analyse the effect of using different material models and spatial distributions for garnet on the erosion behaviour of Al 7075-T6. Three popular material models were considered for garnet, including rigid, linear elastic, and tensile failure models, in addition to the Johnson-Holmquist (JH2) model. These four models were tested and compared for single and multiple particle impact under different waterjet pressures, abrasive mesh sizes, and impact angles. Furthermore, the effect of particle spatial distribution within the jet pass was examined. The model results demonstrated that using different material models for garnet significantly controls the erosion behaviour in AWJM. In addition, the radial distribution of the abrasive particles critically affected the erosion process and kerf geometry, while the axial distribution insignificantly influenced the erosion rate.

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Achieving ultra-low wear of Ti6Al4V alloy by introducing a sinusoidal nitriding layer via nanosecond pulsed laser irradiation

Zhang H., Wang C., Huang H., Yan J., Zhang L., Jiang M., Zhang Z.

Tribology International 200 2024.12

ISSN 0301679X

Introducing wear-resistant layers or constructing microtextures is normally employed to improve the wear resistance of materials. However, single role of the wear-resistant layer or microtexture still could not effectively address the wear issue of titanium alloys. In this study, a sinusoidal nitriding layer is directly fabricated on the Ti6Al4V surface by one-step laser irradiation. Chemical composition and microstructure analysis indicate that the nitriding layer contains TiN and α-Ti phases, and it is metallurgically bonded to the heat-affected zone. Friction wear tests show a 96.9 % reduction in wear rate with dry sliding and 99.6 % with oil lubrication, without exhibiting groove orientation dependence. The wear mechanism is discussed by scrutinizing the morphology of the wear scars and their corresponding cross-sections.

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Influence of crystallinity on micro-nano structure response of Zr-based alloys treated by nanosecond laser

Qian Y., Hong J., Jiang M., Zhang Z., Huang H., Yan J.

Optics and Lasers in Engineering 183 2024.12

ISSN 01438166

Understanding the processes and mechanisms of laser-matter interaction is fundamental to the treatment of materials by using laser-based methods, but it is quite challenging because the response of matter to laser irradiation is influenced by many factors, especially the intrinsic properties of the matter. In this study, the influence of crystallinity on micro-nano structure response of Zr-based alloys (Zr41.2Ti13.8Cu12.5Ni10Be22.5) treated by nanosecond laser is investigated. The microscopic topographies and geometrical dimensions of the laser-induced micro-nano structures formed on the surface of Zr-based alloys with different crystallinity have been explored and compared. The experimental results indicate that the microstructural transformation between micro-concave and micro-convex is observed for both amorphous and crystallized Zr-based alloys, i.e., independent of the arrangement of the internal atomic structure. The geometrical dimensions of the laser-induced micro-nano structures and the critical peak laser power intensity required for the microstructural transformation are different, which can be attributed to the difference in thermal conductivity. Inspired by laser-induced micro-convex, a point-by-point laser patterning technique has been proposed for highly efficient and flexible preparation of micro-nano patterns. Importantly, this patterning technique exhibits ultra-high processing efficiency with a material accumulation rate of more than 1012 μm3/s. This work paves an avenue for understanding the laser-matter interaction and is expected to facilitate the advanced functional applications of Zr-based alloys in many fields.

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Surface morphology formation and subsurface microstructure evolution of zirconia in ultrasonic vibration-assisted burnishing

Huang W., Tsuchida T., Yan J.

Journal of Materials Processing Technology 333 2024.12

ISSN 09240136

Yttria-stabilized zirconia (YSZ) is an outstanding ceramic material with applications in dentistry, biomedical, and mechanical device, where a smooth and durable surface is required. This study employed ultrasonic vibration-assisted burnishing (UVB) to enhance the surface hardness of YSZ while simultaneously reducing its roughness. The surface topography formation, subsurface microstructure evolution, and surface hardness change of YSZ were investigated. It was found that a smooth surface with an average roughness (Ra) of 0.12 μm was achieved using UVB, representing 67.6 % reduction in surface roughness from the original sintered surface, which is attributed to the burnishing-to-cutting phenomenon during the processing. The UVB-induced compression and material densification prevented the formation of the monoclinic phase during the processing of YSZ. Grain refinement and crystal lattice distortion occurring in the subsurface layer led to an increase in surface hardness, reaching up to 19.7 % higher than that of the original sintered surface. Moreover, the UVB-processed surface demonstrated a high resistance to mechanical impacts, effectively inhibiting the tetragonal-to-monoclinic phase transformation in indentation testing. These findings demonstrate that UVB is an effective approach for enhancing the surface and subsurface properties of the material.

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Abnormal wetting behavior transformation in RB-SiC composite induced by laser irradiation and annealing treatment

An H., Qian Y., Zhang Z., Huang H., Yan J.

Chemical Engineering Journal 499 2024.11

ISSN 13858947

Multifunctional reaction-bonded silicon carbide (RB-SiC) surfaces with tailored wetting behaviors have garnered notable interest due to their potential applications across various fields. However, the inherent hard-brittle nature of RB-SiC ceramics poses substantial challenges for the facile and controllable preparation of homogeneous and heterogeneous wetting surfaces via conventional techniques. Herein, taking advantage of the fact that laser irradiation of RB-SiC can induce the formation of SiO2 phase and that SiO2 with high surface energy can inhibit the adsorption of organic matter, the surface wetting characteristics of RB-SiC ceramics are flexibly tuned through a hybrid processing technique combining laser irradiation and annealing treatment. The SiO2 content of the laser-irradiated surface can be regulated by varying the laser processing parameters. In the subsequent annealing process, the laser-irradiated surface with low SiO2 content achieves a wettability transition from superhydrophilicity to superhydrophobicity, whereas the laser-irradiated surface with high SiO2 content remains superhydrophilic. Inspired by annealing-induced significant difference in wettability, gradient wetting and extreme wettability contrast surfaces are prepared, enabling the directional transport of droplets. The homogeneous superhydrophobic surfaces produced at different annealing temperatures exhibit distinct anti-icing capabilities and adhesion properties. Importantly, the prepared superhydrophobic surfaces with varying adhesion forces can achieve no-loss droplet transport. This study provides a straightforward, high-efficient, and low-cost method for fabricating RB-SiC surfaces with diverse wetting behaviors, thereby promising to expand their utility spectrum and practical applicability.

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A cross-scale material removal prediction model for magnetorheological shear thickening polishing

Tian Y., Ma Z., Ma X., Li L., Yan J.

Journal of Materials Processing Technology 332 2024.11

ISSN 09240136

Conventional polishing methods face significant challenges for achieving excellent performance on complex surfaces. The magnetorheological shear thickening polishing (MRSTP) method, with its dual-stimulus response of shear thickening and magnetization enhancement, offers an effective solution for polishing complex surfaces. However, existing models fail to elucidate the cross-scale material removal mechanisms in MRSTP owing to the coupling of magnetic and flow fields. In this study, a comprehensive model was proposed to address the the challenge of predicting the cross-scale material removal rate (MRR) in MRSTP for complex surfaces. Analytical and finite difference methods were employed to solve the pressure distribution during the MRSTP process using magnetohydrodynamics. By incorporating the pressure distribution, an MRR predictive model was developed for arbitrary points on the workpiece surface based on the indentation theory for active abrasive grains. The material removal mechanism was explored by considering elastic and plastic deformation under fluid pressure. The experimental validation showed a relative error of 14.9 % between the theoretical and experimental MRR. Experiments on aero-engine blade tenons demonstrated that the established MRR model is well suited for application to complex surfaces. This study ultimately reveals the material removal mechanism of MRSTP with coupled magnetic and flow field, providing a new foundation for predicting MRR on complex surfaces.

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Bridging Data Gaps: A Federated Learning Approach to Heat Emission Prediction in Laser Powder Bed Fusion

Lei R., Guo Y.B., Yan J., Guo W.G.

Journal of Manufacturing Science and Engineering 146 ( 10 ) 2024.10

ISSN 10871357

Deep learning has impacted defect prediction in additive manufacturing (AM), which is important to ensure process stability and part quality. However, its success depends on extensive training, requiring large, homogeneous datasets - remaining a challenge for the AM industry, particularly for small- and medium-sized enterprises (SMEs). The unique and varied characteristics of AM parts, along with the limited resources of SMEs, hamper data collection, posing difficulties in the independent training of deep learning models. Addressing these concerns requires enabling knowledge sharing from the similarities in the physics of the AM process and defect formation mechanisms while carefully handling privacy concerns. Federated learning (FL) offers a solution to allow collaborative model training across multiple entities without sharing local data. This article introduces an FL framework to predict section-wise heat emission during laser powder bed fusion (LPBF), a vital process signature. It incorporates a customized long short-term memory (LSTM) model for each client, capturing the dynamic AM process's time-series properties without sharing sensitive information. Three advanced FL algorithms are integrated - federated averaging (FedAvg), FedProx, and FedAvgM - to aggregate model weights rather than raw datasets. Experiments demonstrate that the FL framework ensures convergence and maintains prediction performance comparable to individually trained models. This work demonstrates the potential of FL-enabled AM modeling and prediction where SMEs can improve their product quality without compromising data privacy.

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On the promotion of serrated flows and shear band behaviors in a Zr-based metallic glass during ultrasonic vibration nanoindentation

Huang H., Su W., Wei D., Jiang M., Qian Y., Yan J.

Intermetallics (Intermetallics) 173 2024.10

ISSN 09669795

Initiation and evolution of flow units and their correlation with mechanical behaviors of metallic glasses (MGs) are well known significant for understanding the rheological behavior of glassy substances. Here, the evolution of plastic deformation behavior of a typical Zr-based MG induced by ultrasonic vibration is investigated by means of nanoindentation, especially focusing on studying structural evolution through analysis of load-displacement curves. Furthermore, the micro-morphologies of residual indentations are characterized by using the scanning electron microscope (SEM) and atomic force microscope (AFM). Compared to quasi-static nanoindentation tests, a significant reduction in the hardness and elastic modulus of the MG by about 15 % and 30 %, respectively, is observed when subjected to ultrasonic vibration nanoindentation with an amplitude of 0.4 μm, accompanied by a pronounced indentation size effect. In addition, higher ultrasonic vibration amplitude induces larger indentation depth, more pronounced serrated flows in the load-displacement curves and more remarkable shear bands around the residual indentations, indicating ultrasonic vibration-promoted plastic flows in MG. This study provides an insight into the structural origin of plastic flows in MG systems under ultrasonic vibration, which will help to facilitate their application in the fields such as ultrasonic vibration assisted forming.

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Experimental investigation on microstructure, mechanical and optical properties of RB-SiC ablated by nanosecond pulsed laser in nitrogen atmosphere

An H., Qian Y., Zhang Z., Huang H., Yan J.

Composites Part A: Applied Science and Manufacturing (Composites Part A: Applied Science and Manufacturing) 185 2024.10

ISSN 1359835X

Reaction-bonded silicon carbide (RB-SiC) has gained significant attention owing to its exceptional physical and chemical properties. Improving the photovoltaic efficiency and mechanical properties of RB-SiC is conducive to further enhancing its applicability. Laser gas nitriding is an effective strategy to simultaneously reduce the surface reflectivity and enhance the surface hardness of materials. Accordingly, the evolution of microstructure, mechanical and optical properties of RB-SiC composite ablated by nanosecond pulsed laser in nitrogen atmosphere was comprehensively investigated. After laser gas nitriding, the surface hardness of RB-SiC composite was increased by 10.6–44.6 %. The chemical composition analysis indicated that Si-based nitride was formed on the laser-ablated surface, which was mainly responsible for the hardness enhancement. Additionally, the reflectivity of the laser-ablated surface was reduced by up to 95.2 % compared to the original RB-SiC composite. This study provides a straightforward and effective method to simultaneously improve the mechanical and optical properties of RB-SiC composites.

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Improving the surface characteristics of metallic glass thin ribbons by laser gas nitriding

Huang H., Guo H., Wang J., Jiang M., Qian Y., Yan J.

Surfaces and Interfaces 53 2024.10

ISSN 24680230

The single-roll cooling method excels in producing metallic glass ribbons (MGRs), offering rapid cooling rates and exceptional thickness consistency. Nevertheless, a large number of defects including micro-pits and micro-gaps usually appear on the surface of MGRs after the roll forming process, significantly impacting their service life and performance. Laser gas nitriding is a cutting-edge surface modification technology that has been extensively used to improve the comprehensive performance of various metal components. Herein, an attempt was made to simultaneously improve the surface quality and mechanical properties of Zr41.2Ti13.8Cu12.5Ni10Be22.5 MGRs by nanosecond pulsed laser irradiation in a flowing nitrogen atmosphere. The effects of laser irradiation parameters on the surface characteristics of the laser gas nitrided regions were systematically investigated. The experimental results showed that the surface quality of MGRs after laser gas nitriding was enhanced, accompanied by a simultaneous improvement in hardness and scratch resistance. This study underscores laser gas nitriding as a potent strategy to augment the comprehensive surface characteristics of MGRs. This enhancement is poised to significantly extend their service life and reinforce their reliability when utilized as structural and functional materials in sectors such as machinery, national defense, and aerospace.

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A nonlinear dynamic analysis of skidding behavior in rolling bearings using lubricant traction coefficients and cage flexibility

Atef M.M., Khair-Eldeen W., Yan J., Nassef M.G.A.

Tribology International (Tribology International) 197 2024.09

ISSN 0301679X

Skidding is a primary cause of rolling element bearing (REB) failure, which is influenced by operating conditions, lubricant properties, and bearing design. This paper presents an improved nonlinear dynamic model of REBs to analyze the impact of lubricant characteristics on REB skidding at different speed states. The model considers time-varying traction coefficient, cage flexibility, and cage pocket clearance. The selected tested lubricants include lithium grease (LGT2), compound calcium sulfonate (CCS) grease, and 4109 Chinese aviation oil. Simulation results show that CCS grease effectively reduces cage skidding, with the lowest load limits (300 N at 2000 RPM) under constant speed conditions and the highest stable limit (2932 RPM) during acceleration. LGT2 grease exhibits minimal sensitivity to acceleration and fluctuation speed parameters change.

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Significant improvement in surface hardness of CrMnFeCoNi high entropy alloy via nanosecond pulse laser grain refinement

Huang H., Tian X., Wang C., Yan J.

Vacuum (Vacuum) 226 2024.08

ISSN 0042207X

The CrMnFeCoNi alloy with a stable single face-centered cubic (FCC) phase, representing a typical class of high-entropy alloys (HEAs), has garnered considerable attention owing to their exceptional mechanical properties. However, the inherent low hardness has impeded their utilization in structural or contact components. This study attempted to improve the surface hardness of CrMnFeCoNi HEA via grain refinement realized by nanosecond pulse laser irradiation. The effects of laser parameters on the surface microstructures, chemical composition, and mechanical properties were investigated, and the mechanism for grain refinement was analyzed. The experimental results showed that the hardness of the laser-irradiated surface was significantly improved without altering the chemical composition. This study provides a simple but effective method to refine the grain of HEAs and improve their surface hardness.

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Bending Forming Characteristics of CoCrFeMnNi High-Entropy Alloy Sheets Induced by Nanosecond Pulse Laser Irradiation

Tian X., Wang C., Zhang H., Gao J., Huang H., Yan J.

Materials 17 ( 15 ) 2024.07

Laser bending forming, as a flexible and die-less forming approach, facilitates the three-dimensional shaping of sheets through the generation of thermal stress via laser-material interaction. In this study, the bending forming characteristics of CoCrFeMnNi high-entropy alloy sheets induced by nanosecond pulse laser irradiation were systematically investigated. The effects of parameters including laser power, scanning speed, number of scans, scanning interval, and sheet size on the bending angle, cross-sectional morphology, and hardness were studied in detail under both the laser single-line and multi-line scanning modes. The experimental results confirmed the effectiveness of nanosecond pulse laser irradiation for achieving accurate formation of CoCrFeMnNi sheets, with the successful fabrication of J, L, and U-shaped metal components. Apart from the forming ability, the cross-sectional hardness was significantly increased due to the grain refinement effect of nanosecond pulse laser irradiation. Furthermore, employing the laser single-line scanning mode enabled the effective rectification of overbending parts, showcasing complete recovery for small-angle overbending, and a remarkable 91% recovery for larger-angle overbending. This study provides an important basis for the bendability of CoCrFeMnNi sheets by laser forming and elucidates the evolution of the microstructure and mechanical properties in the bending region.

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Surface quality and mechanical property evolution of laser nitrided Zr-based metallic glass induced by laser shock flattening

Huang H., Xu P., Liu B., An H., Qian Y., Yan J.

Vacuum (Vacuum) 224 2024.06

ISSN 0042207X

Laser nitriding is an effective modification technique to improve the comprehensive mechanical properties of metallic glasses (MGs). However, numerous micro-defects, such as pores and humps, usually appear on the laser-nitriding-treated (LNed) MG surface, and therefore additional post-treatment is required. Herein, laser shock processing was implemented to flatten the LNed MG and as well modify its surface mechanical property. The dependence of the laser shock flattening process on the laser energy density was investigated. The results revealed that the surface micro-defects on the LNed MG were significantly reduced after laser shock flattening, and accordingly, the surface roughness (Sa) was decreased, with a maximum reduction of 61.87% (from 0.48 to 0.183 μm) achieved at a relatively high laser energy density of 178.3 J/cm2. Furthermore, nanoindentation measurements indicated that although the surface hardness of the LNed MG was decreased after laser shock flattening, it was still higher than that of the as-cast MG.

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Investigation of failure modes and material structural responses of nanographite coatings on single-crystal silicon by nanoscratching

Brüssel F., Huang W., Yan J.

Tribology International (Tribology International) 193 2024.05

ISSN 0301679X

The failure modes of a nanographite-on-silicon system and the effects of the coating on the load-induced phase transformation of the silicon substrate were investigated using a series of nanoscratching tests with a spherical diamond indenter. The critical normal load for the failure of the nanographite coating was determined based on the thickness of the coating. When the load increased beyond the critical point, cracks, press spallation, and lift spallation were observed, and the silicon substrate underwent a phase transformation from the original crystalline phase to a mixture of amorphous, Si-III and Si-XII phases. For a thin coating, the silicon substrate was free of phase transformation owing to the coating protection. These findings provide guidance for glass molding and other applications.

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Simultaneous flattening and hardening of laser shock peened Zr-based metallic glass surface by nanosecond laser irradiation in a flowing nitrogen atmosphere

Qian Y., Liu B., Hong J., Jiang M., Zhang Z., Zhang L., Huang H., Yan J.

Journal of Materials Processing Technology (Journal of Materials Processing Technology) 326 2024.05

ISSN 09240136

Laser shock peening (LSP) is an ideal surface modification technique which has been extensively applied to improve the room-temperature plasticity of metallic glasses (MGs) by generating extra-deep compressive residual stress region and increasing the free volume content. Nevertheless, after LSP treatment, the surface quality and hardness of MGs are usually impaired simultaneously, which hinders their applications as structural and functional materials. In the current study, an attempt was made to achieve simultaneous flattening and hardening of LSP treated (LSPed) Zr-based MG by nanosecond laser irradiation in a flowing nitrogen atmosphere. The effects of laser power level on the macro- and micro-morphology, chemical composition, surface hardness, and surface roughness (Sa) of the laser-irradiated LSPed MG were comprehensively investigated. It was found that the minor surface defects of the LSPed MGs could be effectively reduced by nanosecond laser irradiation under appropriate laser irradiation parameters, and accordingly, the surface quality was improved (with a maximum reduction in surface roughness (Sa) by 86.3%). Furthermore, the nanoindentation test results indicated that nanosecond laser irradiation at a relatively high laser power of 15.6 W resulted in an impressive improvement (173.9%) in surface hardness of the LSPed MG, which could be attributed to the introduction of hard nitrided phases mainly consisting of Zr3N4. This study provides an insightful understanding of the microstructure changes and surface characteristics of the LSPed MGs after nanosecond laser irradiation in a flowing nitrogen atmosphere, which paves the way for improving the applicability of MGs as structural and functional materials.

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Surface conditioning in cutting and abrasive processes

Schulze V., Aurich J., Jawahir I.S., Karpuschewski B., Yan J.

CIRP Annals (CIRP Annals) 73 ( 2 ) 667 - 693 2024.05

ISSN 00078506

Cutting and abrasive processes affect the surface layer state of the components treated. This determines their performance in service. An adjustment of the surface layer properties would allow for enhanced performance. This paper introduces the influences of named processes on the surface layer state and their systematics. Models and sensor concepts for surface conditioning are described and combined to soft sensors which are the basis for active control within the processes. A validation study and actual applications of the conditioning concept are shown, allowing for further technological and scientific understanding of surface conditioning and its contribution to material and energy efficiency.

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Effect of dopant concentration on femtosecond pulsed laser irradiation of yttria-stabilized zirconia for generating nanopores

Yamamuro Y., Shimoyama T., Nagata H., Yan J.

Journal of Alloys and Compounds (Journal of Alloys and Compounds) 980 2024.04

ISSN 09258388

Yttria-stabilized zirconia (YSZ) is a fine ceramics material that has been applied to dental implants and mechanical components. As YSZ is a hard, brittle, and chemically stable material, that undergoes phase transformation during mechanical loading, it is difficult to fabricate nanostructures using mechanical processing methods. In this study, a surface structuring method using a femtosecond pulsed laser was proposed, which is effective in suppressing the mechanical loading-induced phase transformation. As the material properties of YSZ vary with the concentration of yttria dopant, polycrystalline zirconia samples with different yttria concentrations (2, 3, 5, and 8 mol%) were used to investigate the effect of yttria concentrations on laser processing characteristics for nanostructuring. At all concentrations, nanopore generation in the surface grain was achieved by laser irradiation near the ablation threshold. In addition, there was no significant change in the crystal structure before and after laser irradiation, and no damage to the bulk occurred. At 2 mol%, intergranular cracks were generated around the pores. By increasing the dopant level to 5 mol%, the lens effect of the crystal grains became stronger due to enhanced grain growth, and the diameter and number of pores increased. In addition, pores formed preferentially on smaller grains at 5 mol%. However, for YSZ with 8 mol%, the pore formation phenomenon was different from that in the lower dopant level, as the area near the grain boundary was preferentially ablated, and microcracks formation and exfoliation of the surface also occurred. These results contribute to a deeper understanding of the laser ablation characteristics of zirconia with different dopant levels and to the development of surface structuring methods for fine ceramics materials.

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Enhancing object detection and classification using deep learning: A novel approach with annotated dataset and YOLO-C3GTR architecture

Usman, RM; Yan, JH; Mehmood, S; Jamil, M

MEHRAN UNIVERSITY RESEARCH JOURNAL OF ENGINEERING AND TECHNOLOGY 43 ( 2 ) 205 - 219 2024.04

ISSN 0254-7821

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Change in Material Structure upon Laser Irradiation of Mixed Target of Si Grinding Waste and Graphite Powder

Kanon MINAMI, Kyosuke KOBINATA and Jiwang YAN

Journal of The Japan Scoiety of Electrical Machining Engineers 58 ( 147 ) 3 - 11 2024.03

Research paper (scientific journal), Joint Work, Last author, Accepted

On the surface characteristics and removability of RB-SiC composite processed by nanosecond pulsed laser

An H., Qian Y., Zhang L., Zhang Z., Huang H., Yan J.

Composites Part A: Applied Science and Manufacturing (Composites Part A: Applied Science and Manufacturing) 180 2024.02

ISSN 1359835X

The inherent hard-brittle nature of RB-SiC composite poses significant challenges for efficient machining, hindering its application and promotion. Laser processing is a non-contact treatment technique that can effectively modify the mechanical properties of the material surface, thereby altering its removability. Accordingly, the change in surface characteristics of RB-SiC composite induced by nanosecond laser irradiation was investigated. It was found that laser irradiation could effectively soften the RB-SiC composite (with a maximum reduction in hardness by 40.7%), and the softening degree was strongly dependent on the laser parameters. The chemical composition analysis showed that the SiC content was decreased while the Si content was increased after laser irradiation, which was mainly responsible for the hardness reduction of RB-SiC composite. In addition, compared to the original RB-SiC composite, the laser-irradiated samples exhibited enhanced weight loss during the polishing process. This work gives a feasible route to improve the removability of RB-SiC composite.

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Controlled vibration amplitude in ultrasonic assisted grinding using FRF guided cutting frequency

Mansour M.M., El-Hofy H., Yan J., Maher I., Nassef M.G.A., Khaireldien W.M.

International Journal of Machining and Machinability of Materials (International Journal of Machining and Machinability of Materials) 25 ( 3-4 ) 408 - 431 2024.01

ISSN 17485711

In ultrasonic-assisted machining, vibration amplitudes can be controlled at the resonant frequency by altering the ultrasonic power. However, the availability of amplitude controlled ultrasonic power is constrained to limited types of machine tools. The present study introduces a novel idea for generating identified vibration amplitudes for a diamond-grinding tool by adjusting the ultrasonic frequency in the range from 20 kHz to 30 kHz. For this purpose, experimental model analysis (EMA) is carried out on five different diamond-grinding tools to obtain their frequency response function (FRF) curves. The vibration amplitude is measured using a dial indicator and eddy current sensor methods. Further analysis is conducted using 3D laser microscope after machining to decide the proper measurement method. It is found that various amplitudes can be successfully accurately reached from an individual cutting tool by altering the input ultrasonic frequency according to the generated FRF curve of the tool.

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Surface hardness and scratch characteristics of nanosecond laser colored Ti-based metallic glass

Zhang H., Wu H., Zhang L., Jiang M., Huang H., Yan J.

Journal of Alloys and Compounds (Journal of Alloys and Compounds) 970 2024.01

ISSN 09258388

Pulsed laser irradiation is widely used for coloring metallic glass (MG) surfaces due to its efficient and clean processing characteristics. However, the hardness and tribological properties of laser colored MG surfaces have rarely been studied. In this study, various colors were prepared on Ti-based MGs by nanosecond pulsed laser irradiation, and the mechanical properties of the colored surfaces were subsequently investigated. Before hardness testing, the colored surfaces were slightly polished and characterized for surface morphology and phase composition. The hardness of the colored surfaces was measured by a nanoindentation instrument, and the corresponding load depth curves and residual indentations were obtained. The results showed a 39% increase in hardness compared to the as-cast surface. Scratch tests were performed to investigate the tribological properties of the colored surfaces. The residual scratches and three dimensional (3D) topographies exhibited diverse features, and the scratch damage mechanism was analyzed accordingly. This study broadened the knowledge of surface hardness and tribological properties, and illustrated the application potentials of laser colored MGs.

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Efficiently preserving material resources in manufacturing: Industrial symbiosis revisited

Duflou J.R., Wegener K., Tekkaya A.E., Hauschild M., Bleicher F., Yan J., Hendrickx B.

CIRP Annals 73 ( 2 ) 695 - 721 2024.01

ISSN 00078506

The fraction of materials that does not reach the target product in discrete manufacturing is very significant. Directing secondary material streams towards other manufacturing processes, possibly after intermediate pre-processing, offers opportunities for more energy and resource efficient recycling routes. This paper contributes to the exploration of such symbiotic recycling strategies by identifying relevant process mechanisms and by systematically scanning the manufacturing domain for relevant process combinations. Emerging and proven symbiotic combinations within the discrete manufacturing domain are reviewed, with proper attention for the quantification of the thus avoided environmental impact. A series of representative case studies illustrates the feasibility of applying industrial symbiosis principles in a discrete manufacturing context, with uniform data sheets providing detailed information on relevant research achievements.

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Biodegradable cutting fluids for sustainable manufacturing: a review of machining mechanisms and performance

Gan C.K., Liew P.J., Leong K.Y., Yan J.

International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 131 ( 3-4 ) 955 - 975 2024

ISSN 02683768

The application of biodegradable cutting fluids in metal cutting processes has raised interest among multidisciplinary researchers. Vegetable oils with long and polar fatty acid chains provide thick lubricant coatings that interact strongly with metallic surfaces, making them ideal biodegradable cutting fluids. In this review, the viscosity, oxidation performance, and machining performance of several vegetable oils, including palm, coconut, neem, and jatropha oils, were analysed and compared with conventional cutting fluids. The associated challenges in this field are discussed, and future research directions presented. Through this review, vegetable oils with particle additives, like alumina, silicon dioxide, molybdenum disulfide, and hexagonal boron nitride, were identified to be capable of improving the machining performance. The particles’ mending, polishing, and rolling effects are effective mechanisms for improving machining performance. Furthermore, chemical modification processes, such as transesterification and epoxidation, improve the anti-oxidation ability of vegetable oils by altering the carboxyl group (esterification/transesterification) or the fatty acid chain (epoxidation). Consequently, vegetable oils with particle additives and chemical modification surpass conventional cutting fluids in metal cutting operations and contribute to sustainable manufacturing technologies.

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Influences of tool tip geometry on surface/subsurface damage formation in nanoscratching of single-crystal 4H-SiC

Huang W., Yan J.

Procedia CIRP (Procedia CIRP) 123 185 - 190 2024

ISSN 22128271

Creating a smooth surface finish with nanometer-scale roughness on SiC is extremely difficult due to its hard, brittle properties and crystal anisotropy. In this study, nanoscratching tests were performed on single-crystal 4H-SiC along various crystal directions by using a sharp Berkovich tip (radius ~150 nm) and a blunt spherical tip (radius ~1 μm), respectively, to reveal the effects of tool geometry on its surface integrity. Results indicate that, under the same load conditions, the Berkovich face-forward tip produced the greatest penetration depth, followed by the Berkovich edge-forward tip and the spherical tip. The extent of surface and subsurface damage caused by the three tips follows the same trend as the penetration depth. Phase transformation did not occur in the scratched surface with the three tips, while it was occurred in the chips generated with Berkovich face-forward tip. The critical load for surface crack formation was larger when scratching along <01−10> directions compared to scratching along <11−20> directions, independent of tool geometry. Microcrack-like defects may form in the subsurface even the surface is free of damage. The microcracks were caused by {01−11} pyramidal <a> and <a+c> slip and by {11−22} pyramidal <c+a> slip when scratching along <11−20> and <01−10> directions, respectively.

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Tool Dynamics-induced Surface Topography Error in Fast Tool Servo-Based Diamond Turning of Micro Dome Arrays

Hashimoto T., Yan J.

Procedia CIRP (Procedia CIRP) 123 422 - 427 2024

ISSN 22128271

Micro dome arrays are applied as moulds to injection/press moulding to produce micro lens arrays. Fast tool servo (FTS) based diamond turning is a promising technique for manufacturing such micro dome arrays with high accuracy and machining efficiency. In this study, cutting of micro dome array (MDA) on copper with FTS was performed to evaluate the dynamics behaviour of the tool servo and its effects on surface topography. Results show that local surface speed dramatically affects the servo dynamics behaviour. When the local surface speed is higher than a critical value, overcutting and wavy patterns could be formed on the cut-in area of the domes and exit area, which is caused by the servo response and its limitation. By capturing and analysing the position signal and correlating it with the surface topography of the generated dome surface and considering its limitations, an effective strategy for optimizing micro dome array machining parameters was proposed. MDA cutting tests with optimized cutting conditions achieved a significantly improved form accuracy. This study will guide the optimal use of FTS systems in machining micro structured surfaces.

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Improving and Predicting the Surface Roughness and the Machining Accuracy in Ultrasonic Vibration-Assisted Milling

Baraya M., Yan J., Hossam M.

Journal of Vibration Engineering and Technologies (Journal of Vibration Engineering and Technologies) 12 ( Suppl 1 ) 127 - 140 2024

ISSN 25233920

The present research work amis to develop a controlled vibratory system for improving the performance of slotting process based on the vibration-assisted milling technique. In addition, the establishment of a statistical model for predicting the process efficiency was a key aim target. In the current investigation, an ultrasonic vibratory device was designed to provide vibration oscillations in the cutting feed direction to the 7075 aluminum alloy workpiece side at 34.7 kHz frequency and 10 μm amplitude. A LabView code has been developed to control the input vibration parameters. A full factorial design of experiments with 4 factors and 2 levels was conducted. An in-depth statistical analysis is then implemented to study the effect of machining and vibration parameters on the process performance. Then, a statistical model for predicting the process response in terms of cutting force, surface roughness, and machining accuracy has been established. Some experiments showed a significant reduction in cutting force up to 50% in the feed direction. Additionally, an improvement in workpiece surface roughness was recorded. Regarding the machined surface accuracy, introducing ultrasonic vibrations significantly reduces the produced slot width error compared to Conventional Milling (CM). The developed statistical model shows a very well agreement with the experimental results. Therefore, the developed VAM technique is suitable for manufacturing parts that require high geometrical and dimensional accuracy.

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Investigation on Monitoring Personal Health via Internet of Things-Based Wearable Device

Ngo H.Q.T., Nguyen L.D., Huynh P.K., Le T.Q., Yan J.

EAI/Springer Innovations in Communication and Computing 693 - 704 2024

ISSN 25228595

In our era, smart clothes for personal health monitoring in home care is a promising and innovative approach. These clothes are integrated with sensors and electronic devices that could follow vital signs, levels of activities, and other health metrics. Therefore, in this paper, the design of such smart clothes and their potential applications are presented to realize the novel concept in the healthcare service. Using various sensors, it is expected to obtain the health parameters or habitual activities of patients, while this cloth still maintains personal comfortability. Then, data is collected and transmitted via wireless communication to host server. Owing to this design, several algorithms could be deployed to predict any abnormal health status. Additionally, this approach could reduce the burden care from medical staff or nurses who are in the over-work circumstance. From this achievement, the potential applications of smart clothes on healthcare and the future research directions could be outlined clearly in the related fields.

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Achieving superhydrophobicity of Zr-based metallic glass surface with anti-corrosion and anti-icing properties by nanosecond laser ablation and subsequent heat treatment

Cui M., Huang H., Wu H., Zhang L., Yan J.

Surface and Coatings Technology (Surface and Coatings Technology) 475 2023.12

ISSN 02578972

Water repellency of superhydrophobic surfaces offers an opportunity to enhance the corrosion and icing resistance of metallic glasses (MGs). Inspired by the “lotus effect” in nature, hierarchical micro/nanostructures were constructed on a Zr-based MG surface using nanosecond laser ablation. By subsequent heat treatment in air, the structured surface showed a water contact angle (CA) of 168.2 ± 1.5° and a sliding angle (SA) of 4 ± 0.7° (adhesion force of 9.8 ± 1.7 μN), exhibiting repellency and low adhesion to water. Specifically, the superhydrophobic surface stored in air and immersed in water possessed stability and durability, and the superhydrophobic surface still maintained superhydrophobicity after mechanical scratching. The heat treatment temperature worked as a switch for controlling the wettability transition, and by tuning the temperature, the structured surface can switch from superhydrophobicity (CA: 168.2 ± 1.5°) to superhydrophilicity (CA: ~0°). Furthermore, compared to the polished MG surface, the superhydrophobic surface increased the corrosion resistance and freezing time, and delayed the freezing temperature. This study provides a facile non-fluorinated method for fabricating superhydrophobic MG surfaces with anti-corrosion and anti-icing properties, which would enhance the application of MGs as structural and functional materials under extreme conditions.

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Surface conditioning of zirconia ceramic by enhanced ultrasonic vibration-assisted burnishing

Tsuchida T., Huang W., Yan J.

Production Engineering (Production Engineering) 18 ( 2 ) 353 - 366 2023.12

ISSN 09446524

Yttria-stabilized zirconia (YSZ) ceramic is a widely used material in mechanical and biomedical engineering, such as machine parts and dental implants. For most applications, surface conditioning methods are required to produce smooth and reinforced surfaces with compressive residual stress. This paper investigates the processing characteristics of YSZ under ultrasonic vibration-assisted burnishing (UVB) enhanced by flexible stage and tool rotation techniques, respectively. For the use of flexible stage-enhanced UVB, the fluctuation of burnishing force was greatly reduced. As results, a smooth surface with a roughness of 164 nm Ra was obtained, which shows 39.7% surface roughness reduction from the original surface, and 9.4% surface roughness reduction from the surface burnished with conventional UVB. The burnished surface yielded strong residual compressive stresses of 401 MPa in the burnishing direction and 695 MPa in the step-feed direction. For the use of tool rotation-enhanced UVB, tool rotation-induced arc-shaped surface textures were formed on the burnished surface, and the textures became more distinct and denser as the rotation speed increased. The surface roughness was reduced by 58.9% from the original surface with the tool rotation-enhanced UVB. Stress-induced phase transformation of YSZ was identified in all burnished surfaces. This study demonstrates the feasibility of one-step manufacturing of a smooth surface with high residual compressive stress, which expands the applications of YSZ.

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Ultra-low wear of titanium alloy surface under lubricated conditions achieved by laser texturing and simultaneous nitriding

Wang C., Huang H., Wu H., Hong J., Zhang L., Yan J.

Surface and Coatings Technology (Surface and Coatings Technology) 474 2023.12

ISSN 02578972

Titanium and its alloys are widely used in aerospace and biomedical fields but suffer from poor tribological properties. Surface coating and texturing have proven to be effective ways for improving tribological properties. However, integrating these methods may introduce complexity and increased costs. In this study, laser nitriding and surface texturing were simultaneously achieved on Ti6Al4V surface via a nanosecond pulse laser. The tribological properties of textured surfaces under lubricated conditions were investigated, and the wear mechanism was discussed. Experimental results showed significant improvements in the tribological properties, including a smaller and stable coefficient of friction (COF) and a remarkable 99.3 % reduction in wear rate. This study provides valuable insights for improving the tribological properties of titanium alloys, benefiting industrial and biomedical applications.

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Formation of Laser-Induced Periodic Surface Structures on Reaction-Bonded Silicon Carbide by Femtosecond Pulsed Laser Irradiation

Meshram T., Yan J.

Nanomanufacturing and Metrology (Nanomanufacturing and Metrology) 6 ( 1 ) 2023.12

ISSN 2520811X

Reaction-bonded silicon carbide (RB-SiC) is an excellent engineering material with high hardness, stiffness, and resistance to chemical wear. However, its widespread use is hindered due to the properties mentioned above, making it difficult to machine functional surface structures through mechanical and chemical methods. This study investigated the fundamental characteristics of laser-induced periodic surface structures (LIPSSs) on RB-SiC via femtosecond pulsed laser irradiation at a wavelength of 1028 nm. Low-spatial-frequency LIPSS (LSFL) and high-spatial-frequency LIPSS (HSFL) formed on the surface along directions perpendicular to the laser polarization. SiC grains surrounded by a large amount of Si show a reduced threshold for LIPSS formation. By varying laser fluence and scanning speed, HSFL–LSFL hybrid structures were generated on the SiC grains. Transmission electron microscopy observations and Raman spectroscopy were carried out to understand the formation mechanism of the hybrid LIPSS. A possible mechanism based on the generation of multiple surface electromagnetic waves due to the nonlinear response of SiC was proposed to explain the hybrid structure formation. Furthermore, the direction of laser scanning with respect to laser polarization affects the uniformity of the generated LIPSS.

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Multilayer Graphene-Coated Silicon Carbide Nanowire Formation Under Defocused Laser Irradiation

Minami K., Kobinata K., Yan J.

Nanomanufacturing and Metrology (Nanomanufacturing and Metrology) 6 ( 1 ) 2023.12

ISSN 2520811X

Graphene-coated silicon carbide (SiC@C) core–shell nanostructures have attracted attention in the fields of energy storage and nanoelectronics. In this study, multilayer graphene-coated silicon carbide (SiC) nanowires were obtained through the laser irradiation of a mixture target of graphite powder and silicon (Si) grinding sludge discharged from Si wafer manufacturing. Laser irradiation was performed using an ytterbium (Yb) fiber pulsed laser with a pulse width of 10 ms and a wavelength of 1070 nm with various defocus distances. The effect of laser defocusing on the morphology of the generated nanostructures was investigated. Results showed that nanowires were produced under the defocused conditions, and nanoparticles were observed at the on-focus position. The products obtained under all defocused conditions showed a core–shell structure, and the SiC nanowires were covered by graphene layers. The aspect ratio of the nanowires increased with the defocus distance. Observation of the laser-induced plume using a high-speed camera showed that when the laser was defocused, the plume propagation speed slowed down, and the shape of the plume changed to a swirling vortex. The nanowire formation was closely related to the propagation speed and shape variation of the plume. This successful production of SiC@C core–shell nanowires from Si waste opens up the possibility of the sustainable development of new materials for energy storage and nanoelectronics.

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Fabrication of microlens arrays on single-crystal CaF<inf>2</inf> by ultraprecision diamond turning

Huang W., Nagayama K., Yan J.

Journal of Materials Processing Technology (Journal of Materials Processing Technology) 321 2023.12

ISSN 09240136

Single-crystal calcium fluoride (CaF2) is considered a superior optical material with good transmittance in a wide transmitted wavelength region. However, the production of high surface quality freeform surfaces on CaF2 is difficult owing to its soft, brittle, and anisotropic properties. This study attempted to fabricate spherical and hexagonal microlens arrays on CaF2 using diamond turning with a slow tool servo. In addition, the machining characteristics of CaF2 were systematically investigated. It was found that microcracks tended to be generated in the cut-in and cut-out regions of the lenses. When cutting along the [− 211] and [11 − 2] directions, the machined surfaces were very prone to cracking. When reducing the maximum undeformed chip thickness to less than approximately 60 nm, continuous ribbon-like chips were formed throughout the cutting process, and all lenses were machined in ductile mode without surface cracking. In addition, a spherical microlens array was successfully fabricated in ductile mode with a surface roughness of approximately 2 nm Sa. Consequently, a hexagonal microlens array with sharp edges and crack-free surfaces was achieved using the proposed depth-offsetting segment cutting method. The surface roughness was approximately 4.1 nm Sa with a form error of approximately 147 nm P-V (peak to valley). Tool wear was insignificant until a machining distance of approximately 50 m; however, with further increase in the machining distance, crater wear and microchipping were observed. This study demonstrated the feasibility of fabricating high-quality freeform microstructured surfaces on CaF2 and other soft-brittle materials via diamond turning.

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Analysis and development of elliptical tool path in trochoidal milling

Wagih M., Maher I., El-Hofy H., Yan J., Hassan M.A.

CIRP Journal of Manufacturing Science and Technology (CIRP Journal of Manufacturing Science and Technology) 47 168 - 183 2023.12

ISSN 17555817

Trochoidal milling has been developed to extend the cutting tool life as compared to conventional milling. It is widely used in the machining of slots and corners of molds and dies. There are several tool paths typically used in trochoidal milling such as true, circular, variable-feed, and variable-step trochoidal tool paths. However, these paths suffer from low material removal rates, low surface qualities, high CPU processing times, and/or the requirement of high-dynamic machine tools. Elliptical trochoidal tool path showed its capability to improve the material removal rate, but the expected low surface quality of the produced slot. In this paper, the elliptical tool path will be analyzed analytically and experimentally. The effect of elliptical tool path on material removal rate, cutting forces, walls waviness, and surface roughness have been investigated. A novel linear elliptical-based tool path has been proposed to enhance the elliptical tool path performance by improving both material removal rate and surface quality. A Performance index has been utilized to evaluate the performance of these processes. An analytical model for the local maximum chip thickness in elliptical tool path has been conducted to correlate this path with the cutting forces. The slot walls waviness has been modeled based on the cutting tool path geometry and validated experimentally with error less than 11%. The experimental results showed that the elliptical tool path improved the material removal rate by 11%, with a slight reduction in the maximum resultant cutting force by 3%. On the other hand, the walls waviness and surface roughness have been increased by 45% and 38% respectively as compared to the typical true trochoidal tool path. The introduction of linear paths at the elliptical path sides in the linear-elliptical tool path improved the performance index about 18 times by improving the material removal rate, waviness, and surface quality by 5%, 300%, and 74% respectively, without a significant effect on cutting forces. Therefore, the novel linear-elliptical paths are promising tool paths in increasing the performance of trochoidal milling due to the improved material removal rate, walls waviness, and surface quality, without a significant effect on cutting forces, which will improve the process machinability and cost-effectiveness.

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Laser polishing and simultaneous hardening of the electrical discharge machined Zr-based metallic glass surface

Hong J., Huang H., Zhang L., Zhang Z., Jiang M., Yan J.

Materials & Design (Materials and Design) 237 2023.12

ISSN 02641275

Wire electrical discharge machining (WEDM) is highly suitable for processing the hard-brittle materials like metallic glasses (MGs). However, the electro-thermal energy conversion involved in the WEDM process inevitably introduces some surface defects including bulges, discharge craters, and recast materials on the WEDMed MG surface, which significantly impedes its practical application. Here, an emerging automated polishing technology, laser polishing (LP), was performed in the nitrogen-rich environment to simultaneously improve the surface quality and hardness of the WEDMed Zr-based MG surface. The detailed effects of LP parameters on the surface roughness and morphology were systematically investigated. The morphology evolution and temperature distribution of the molten pool during LP were analyzed by simulation analysis. The experimental results indicated that after single LP of four representative WEDMed Zr-based MG surfaces using the optimized laser parameters, the surface roughness (Sa) was remarkably reduced from 1.27, 2.10, 3.49, and 4.58 μm to 0.09, 0.14, 0.17, and 0.21 μm, respectively, accompanied by an increase in surface hardness from 6.30 GPa to 7.39, 7.67, 8.51 and 8.99 GPa. This study demonstrated that LP could effectively achieve simultaneous enhancement of the quality and hardness of WEDMed MG surfaces, which would contribute to expanding the application prospects of MGs.

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Femtosecond Pulsed Laser Irradiation of Zirconia for Embedding Silver Nanoparticles in Surface Nanopores

Yamamuro, Y; Shimoyama, T; Nagata, H; Yan, JW

Applied Sciences (Applied Sciences (Switzerland)) 13 ( 24 ) 2023.12

Featured Application: Functional surfaces of zirconia with antibacterial properties. Femtosecond pulsed laser irradiation was performed to investigate the feasibility and fundamental characteristics of embedding silver nanoparticles onto zirconia ceramic surfaces. By irradiating laser, nanopores were fabricated on the surface of the yttria-stabilized zirconia (YSZ) substrate, and silver nanoparticles were infiltrated and immobilized into the pores using a commercial nano-silver dispersion solution. Numerous nanopores embedded with silver nanoparticles were successfully obtained on the YSZ surface while keeping the grains’ shapes unchanged by controlling laser parameters. Optimizing laser fluence and scanning speed near the ablation threshold made it possible to remove only the excess dispersant that remained on the surface while keeping silver in the pores and without causing machining of the surface of the YSZ substrate. In addition, about 60% embedding in the nanopores was achieved. It was found that the shorter pulse width was suitable to avoid evaporating both dispersant and silver. Cross-sectional observation revealed that the silver nanoparticles were agglomerated to form clumps and were embedded without a gap at the bottom of the pores at a depth of about 600 nm. After laser irradiation, no significant laser-induced phase change was observed in the YSZ substrate, indicating that there was no in-process thermal damage to the bulk. These findings demonstrated the possibility of adding a metal nanoparticle to the zirconia surface by using only a laser process without damaging the properties of the base material during the process. New applications of zirconia, such as the generation of functional surfaces with antibacterial properties, are expected.

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Electrical discharge machining of Ti6Al4V alloy with nitrogen gas assistance

Liu Z., Li L., Yan J., Liu X., Meng J., Bai X.

International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 129 ( 5-6 ) 2609 - 2620 2023.11

ISSN 02683768

Due to its exceptional performance, the Ti6Al4V alloy finds extensive use in aviation, biomedical, and petrochemical sectors. Nonetheless, its limited machinability and subpar wear resistance have hindered its widespread application. Therefore, this study underlooks a novel approach by employing nitrogen (N2) gas–assisted electrical discharge machining (NA-EDM) to machine Ti6Al4V. In this context, N2 gas serves a dual purpose. On the one hand, the flow of N2 has a beneficial impact on enhancing the surface properties of the workpiece. On the other hand, N2 reacts with titanium (Ti) to create titanium nitride (TiN), enhancing the component’s performance. Also, this study focuses on investigating how peak current, pulse-on time, electrode rotation speed, and gas pressure influence various aspects, including surface morphology, surface roughness, the microstructure of the recast layer, the microhardness of the recast layer, the thickness of the recast layer, and material removal rate (MRR). Experimental findings show that the NA-EDM process results in a smoother surface morphology, a uniform recast layer, and a reduced MRR. The microhardness in NA-EDM exceeds that of EDM by 42.1%, attributed to the formation of TiN and martensite. Ra is decreased by 21.2% compared to EDM. This study offers novel insights into machining Ti6Al4V alloy, opening up possibilities for broader-scale applications.

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Tool wear and surface integrity in liquid nitrogen clean cutting of cobalt-based superalloy GH605 with AlTiN coated tools

Li X., Zheng G., Yan J., Cheng X., Li Y., Cui E.

Wear (Wear) 530-531 2023.10

ISSN 00431648

The tool wear is severe and the machined surface quality is low in dry cutting of cobalt-based superalloy. The traditional coolant is harmful to the environment and not in line with sustainable development. The liquid nitrogen (LN2) clean cutting of cobalt-based superalloy GH605 using AlTiN coated tools is proposed in this work. The tool wear mechanism and the machined surface integrity are investigated. The results show that, with the decrease of LN2 injection temperature, the sharp wear stage of the tool can be delayed. The injection temperature directly affects the tool life. Compared with dry cutting, the tool life is increased by 42.5% at LN2 injection of −190 °C. Under the lower liquid nitrogen condition, the coating peeling is reduced on the rake face. The decrease of LN2 injection temperature can effectively reduce the damaged area of the flank face and inhibit the oxidation wear. The injection temperature between −30 °C and −150 °C can significantly reduce the surface roughness. The minimum surface roughness value at the injection temperature of −90 °C is 0.486 μm, which is 39.4% lower than that at dry cutting condition. When the LN2 injection temperature is below −90 °C, the thickness of the white layer is less than half of that in dry cutting condition. The hardness of the machined surface is enhanced and the residual stress is reduced at injection temperature below −150 °C. This work demonstrates the possibility of improving the machinability of cobalt-based superalloy by optimizing the LN2 injection temperature.

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Nanosecond laser coloration of Ti-based metallic glass under various laser parameters and irradiation atmospheres

Zhang H., Wang C., Huang H., Zhang L., Yan J.

Journal of Non-Crystalline Solids (Journal of Non-Crystalline Solids) 618 2023.10

ISSN 00223093

Laser coloration is an emerging technique for surface functionalization of metallic glasses (MGs). Understanding the influence of laser parameters on surface color of MGs will accelerate their commercialization. Herein, surface coloration was conducted on a Ti-based MG, and the hue–saturation–intensity (HSI) color space was employed to evaluate color variation. Various colors were achieved by varying the average power and scanning speed in an ambient atmosphere. The results indicated that the overlap rate and number of repetitive scans had a negligible effect on the color and significantly changed the microscopic morphology. The irradiated surfaces were yellowish and colorless in nitrogen and argon atmospheres. Furthermore, the effect of morphology on the surface color and the mechanism of surface coloration were examined. This study demonstrates that nanosecond laser irradiation is an effective method for achieving surface coloration of MGs, which is expected to enrich the surface functionality of MG products.

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Grain visualization of FeCoCrMnNi and AlCoCrFeNi<inf>2.1</inf> high-entropy alloys by nanosecond pulse laser irradiation

Wang C., Huang H., Zhang H., Zhang L., Yan J.

Vacuum (Vacuum) 216 2023.10

ISSN 0042207X

Characterizing grains is the most common method in materials science research, but the existing techniques for grain characterization are generally expensive and time-consuming. In this study, nanosecond pulse laser irradiation with low laser fluence is attempted to visualize the grains of two typical high-entropy alloys (HEAs) with different crystal structures and elemental compositions. The effects of laser parameters and gas atmospheres on the laser visualization of grains are comparatively investigated. Under specific laser irradiation conditions, the grains of these two HEAs could be well visualized by producing different surface nanostructures. By experiments and analysis, the underlying mechanisms of laser visualization of grains under different conditions are elucidated, and the role of O element on the promotion of the visualization of grain boundaries is confirmed. This study provides a simple and efficient method to visualize the grains of HEAs, and on the other hand, enhances the understanding of nanosecond laser-HEA interaction.

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Achieving superhydrophobicity of the FeCoCrMnNi surface via synergistic laser texturing and low temperature annealing

Wang C., Huang H., Cui M., Zhang Z., Zhang L., Yan J.

Journal of Laser Applications (Journal of Laser Applications) 35 ( 3 ) 2023.08

ISSN 1042346X

Superhydrophobic surfaces are highly desirable due to their remarkable water-repellent behavior. Laser texturing with subsequent low surface energy modification is a versatile strategy for creating such surfaces. In this study, via synergistic laser texturing and low temperature annealing, superhydrophobicity was first attempted to be achieved on the FeCoCrMnNi surface. By optimizing the laser parameters, the arrays with large depth-to-width ratios were constructed. Subsequently, by annealing at a low temperature, the transition process from superhydrophilicity to superhydrophobicity was successfully achieved on the FeCoCrMnNi surface. The effects of the hatching interval on the wettability were investigated, and the mechanism of wettability transition for FeCoCrMnNi was discussed. According to the experimental results and analysis, the textured surfaces exhibited excellent superhydrophobicity at different hatching intervals and a maximum contact angle of 165° was obtained. Furthermore, the created superhydrophobic surfaces possessed good liquid capture and self-cleaning capabilities and enabled magnification for optical imaging. The wettability transition after low temperature annealing was attributed to the absorption of airborne organic compounds. This study provides an efficient, clean, and versatile strategy to achieve superhydrophobicity of the FeCoCrMnNi surface by laser processing.

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Laser repairing of FeCoCrNiV high-entropy alloy and its mechanical and cutting characteristics

Wang C., Huang H., Zhang H., Zhang L., Yan J.

Journal of Materials Processing Technology (Journal of Materials Processing Technology) 317 2023.08

ISSN 09240136

High-entropy alloys (HEAs) are promising structural and functional materials owing to their superior mechanical and chemical properties. High surface quality and good machinability are essential for micro-machining high-end precision equipment. Here, laser repairing (LR) was firstly employed to eliminate surface defects and improve the machinability of FeCoCrNiV. After LR, the microstructures and mechanical properties of FeCoCrNiV were investigated. The results show that the surface morphology and chemical composition uniformity of FeCoCrNiV were significantly improved after LR, in which the high melting-point V-rich precipitates concentrated on the original surface were homogeneously distributed throughout the substrate. The surface hardness decreased from 10.5 to 4.5 GPa due to the growth of grains, and the hardness distribution became more homogeneous after LR, providing the opportunity to improve its machinability. In ultrasonic vibration diamond turning tests, the machined surface quality, tool wear, and cutting chips indicated that the laser-repaired material exhibited superior machinability. A sinusoidal free-form surface with high surface quality was then constructed by ultrasonic vibration-assisted diamond turning on the laser-repaired surface. This study provides a method to repair surface defects of HEAs and improve their machinability, which is beneficial to their practical applications.

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Mechanisms of tool-workpiece interaction in ultraprecision diamond turning of single-crystal SiC for curved microstructures

Huang W., Yan J.

International Journal of Machine Tools and Manufacture (International Journal of Machine Tools and Manufacture) 191 2023.07

ISSN 08906955

Single-crystal silicon carbide (SiC) is one of the most attractive materials for electronics and optics but extremely difficult to cut owing to its hard and brittle properties. While in previous studies, the focus has been placed on machining flat surfaces, in this study, the mechanisms of tool-workpiece interaction in cutting curved microstructures on 4H–SiC (0001) were explored through the ultraprecision diamond turning of micro-dimples. The surface/subsurface of both machined workpieces and used diamond tools were characterized, and the machining characteristics, such as chip formation and cutting forces, were also investigated. It was found that microcracks occurred easily in the feed-in/cut-in area of the dimples, which is caused by a large friction-induced tensile stress due to a large thrust force. The dimples located on the secondary cleavage directions <10−10> (S-dimples) were easy to produce crack-free surfaces, while the dimples located on the primary cleavage directions <−12−10> (P-dimples) were very prone to cause cracks on surfaces, even though the chips were formed in a ductile mode. The dimples located on the in-between direction (I-dimples) were moderately prone to surface cracking. It was also found that although the S-dimple has a crack-free surface, it has the thickest subsurface damage (SSD) layer containing a disordered layer, dislocations, and stacking faults; the SSD layer of the P- and I-dimples do not contain stacking faults; and the SSD layer of the I-dimple is the thinnest. Flank wear with nanoscale grooves on the diamond tool was significant without edge chipping and diamond graphitization detected. By optimizing the cutting conditions, a crack-free micro-dimple array was fabricated with nanometric surface roughness. The findings from this study provide guidance for the manufacture of curved SiC parts with high surface integrity, such as molds for replicating microlens arrays and other freeform surfaces on glass.

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A theoretical and deep learning hybrid model for predicting the surface roughness of diamond-turned polycrystalline materials

He Chunlei, Yan Jiwang, Wang Shuqi, Zhang Shuo, Chen Guang, Ren Chengzu

International Journal of Extreme Manufacturing (International Journal of Extreme Manufacturing) 5 ( 3 ) 2023.06

ISSN 2631-8644

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Antireflective structured surface of chalcogenide glass fabricated using glass to glass molding

Zhu Z., Zhou T., He Y., Yu Q., Wang X., Yan T., Yan J., Ruan H.

Ceramics International (Ceramics International) 49 ( 17 ) 28216 - 28223 2023.06

ISSN 02728842

Chalcogenide (ChG) glasses with micro-nano structure arrays are increasingly demanded in infrared optical systems owing to their excellent antireflective properties, and can be mass-produced by precision glass molding (PGM). Nickel-phosphorus (Ni–P) plated molds are commonly used in the PGM process, but the Ni atoms tend to react with the ChG glass at high temperatures. In this study, we propose a novel two-step PGM process. A Ni–P mold is used to transfer antireflective micro-nano structure array to silicate glass. Then the silicate glass, which has a higher glass transition temperature (Tg) than the ChG glass, is used as the mold to replicate the antireflective structured surface to the ChG glass. The results show that the ChG glass micro-nano structure array has high forming accuracy and favorable infrared optical transmission characteristics. The silicate glass is proved to be an appropriate mold material for the ChG glass molding process. This work provides a novel type of the PGM techniques for ChG glass materials.

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Microgrooving of ferrous metals by using cBN tools with laser-modified edges

D. Kitagawa, T. Meshram J. Yan

Journal of the Japan Society for Abrasive Technology 67 ( 6 ) 341 - 346 2023.06

Research paper (scientific journal), Joint Work, Corresponding author, Accepted

A novel calibration method for angular misalignment in independently controlled fast tool servo-based diamond turning

Tanikawa S., Sato Y., Yan J.

Precision Engineering (Precision Engineering) 83 216 - 227 2023.06

ISSN 01416359

With significant technological progress in optics fields, such as VR and 3D sensing technologies, the demand for optical components with complex shapes (e.g., freeform surfaces) has expanded significantly in recent years. Ultra-precision diamond turning is one of the common manufacturing methods used for freeform optics. There are two tool-motion mechanisms for freeform diamond turning: slow tool servo (STS), which moves the entire tool rest, and fast tool servo (FTS), which only drives the diamond tool. In particular, high-frequency and long-stroke FTS units driven by a separate control system from the machine tool controller have recently been developed as a new trend in FTS-based diamond turning. However, this type of independent FTS control system causes a time delay between the machine tool instruction and the FTS tool motion. Even a millisecond-scale time delay can cause a considerable angular misalignment owing to the high rotation rate of the spindle, resulting in a micron-scale form error on the workpiece surface. In this paper, a novel method for precisely measuring the time delay from the machined workpiece surface and compensating for the misalignment based on the measured time delay was proposed. To measure the time delay, spherical dimples were machined on the workpiece surface by using STS and FTS. Subsequently, the angular misalignment and time delay were obtained by comparing the measured surface profiles at specific positions of the spherical dimples. Thus, the time delay can be measured with microsecond-scale accuracy. Based on the measured time delay, the shifted tool position along the spindle axis by the time delay was compensated to the ideal tool position by considering the cutting velocity. Consequently, the angular misalignment was completely eliminated, and submicron-level form accuracy was achieved. This calibration method of angular misalignment for an independent FTS unit is expected to significantly improve the accuracy of ultra-precision machining of freeform optics.

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Tailoring the surface characteristic of metallic glass for wettability control

Qian Y., Liu H., Zhang L., Jiang M., Huang H., Yan J.

Journal of Materials Research and Technology (Journal of Materials Research and Technology) 24 7040 - 7046 2023.05

ISSN 22387854

Bulk metallic glasses (BMGs) have attracted broad research interest in industrial and commercial fields due to their outstanding mechanical and physical properties. Achieving controlled manipulation of their surface wettability is expected to further improve their applicability. In this study, the functional MG surfaces with various wetting behaviors (including superhydrophilicity, superhydrophobicity, gradient wettability, coexistence of superhydrophilicity and superhydrophobicity) were fabricated by controlling the surface microstructure and chemical composition, which were achieved by laser processing and low-temperature heat treatment. The laser-patterned MG surface with hierarchical micro/nanostructures showed hydrophilicity, and it turned to hydrophobicity after heat treatment, which could be attributed to the adsorption of organic matter from the ambient air. The fabricated gradient wetting surface achieved directional transport of droplets, and the constructed extreme wetting contrast surface exhibited good ability in controlling the spreading of droplets.

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The scratch characteristics of laser nitrided Zr-based metallic glass surface

Hong J., Wu H., Huang H., Zhang L., Zhang Z., Jiang M., Yan J.

Intermetallics (Intermetallics) 155 2023.04

ISSN 09669795

Improving the surface hardness and tribological characteristics of metallic glasses (MGs) is meaningful for their applications as surface contact materials. In this study, nanosecond laser nitriding was performed on Zr-based MG to improve its surface properties. Three types of laser nitrided surfaces with different hardness were prepared, and their tribological characteristics were systematically investigated by means of the scratch test. The experimental results indicated that compared with the as-cast MG, the hardness of these three laser nitrided surfaces was increased by 47.94%, 114.56%, and 171.99%, and their coefficients of friction were reduced by 29.12%, 65.05%, and 71.84%, respectively. Furthermore, the residual scratches and surrounding chips exhibited various features under different conditions, and the scratch damage mechanisms were analyzed accordingly.

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Study on the non-free plastic shear removal of material and cutting-induced deformation of micron-submicron grooves

He Y., Zhou T., Kumar A.S., Wang X., Yan J.

Journal of Materials Processing Technology (Journal of Materials Processing Technology) 317 2023.04

ISSN 09240136

The shear interference and chip removal interference between different tool edges during non-free cutting are the main reasons for the deformation of micron-submicron grooves. To our best knowledge, the understanding of the non-free cutting of micron-submicron grooves is still not well established. This paper provides new insight into the material removal mechanism and cutting-induced deformation of micron-submicron grooves in non-free cutting. A novel variable shear angle removal model, revealing the difference of material shear at different positions of the tool edge, is established by infinitesimally segmenting the tool edge after analyzing the shear interference and chip removal interference mechanisms. An equation of the local shear angle enables the mathematical derivation of the topography of the shear surface and chip cross-section in the non-free cutting of micron-submicron grooves. The distribution of shear stress in the shear zone is calculated by establishing the relationship between the shear angle and shear stress based on the unequal division shear zone (UDSZ) theory and Johnson-Cook theory. Furthermore, a mechanics model of micron-submicron groove cutting, revealing the deformation mechanism of the micron-submicron grooves, is established using the differential cutting force method. Finite element simulations and high-speed cutting experiments are conducted to analyze the cutting microstate between the tool and the material and the dynamic deformation of the micron-submicron grooves during non-free cutting. The stress trend of the elastic nodes on the tool edge verifies the mechanics model, and the chip morphology verifies the formation of the shear surface and chips. The degree of non-free cutting is higher at the tool edge infinitesimal segments (TEISs) closer to the tool tip, resulting in a smaller shear angle, which makes the extrusion stress suffered by the groove increases nearly twice from top to bottom. The material flow due to dynamic deformation causes the relative cutting line of the rear-side tool edge to shift forward. The deformation of the micron-submicron grooves is related to the stiffness of the structure.

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Generation of nanopore structures in yttria-stabilized zirconia by femtosecond pulsed laser irradiation

Yamamuro Yuka, Shimoyama Tomotaka, Yan Jiwang

Journal of Materials Research and Technology (Journal of Materials Research and Technology) 23 1155 - 1176 2023.03

ISSN 2238-7854

Femtosecond pulsed laser irradiation of yttria-stabilized zirconia (YSZ) was performed to investigate the feasibility and fundamental characteristics of nanopore structure fabrication. Numerous nanopores were successfully generated on the YSZ surface with only a single laser pulse shot by controlling laser power near the ablation threshold. The nanopore generation mechanism involves light focusing by the convex shape of a crystal grain and ablation inside the grain. By increasing laser power, the number of nanopores increased. Cross-sectional observation revealed that the depth of nanopores was about 500 nm, and nanopores were generated inside the YSZ grains of the top layer while keeping the grains' shapes unchanged. It was found that higher scanning speed and a small number of scans enabled nanopores fabrication without changing the original surface shape, avoiding the removal of the surface layer. Laser-irradiated surfaces of YSZ were characterized by Raman spectroscopy, and it was found that there was no significant phase change in the specimen after nanopore generation compared with the original YSZ surface, confirming that there was no thermal damage to the bulk material. The surface with nanopores showed an enhancement in surface hydrophilicity. These findings demonstrated the possibility of selectively generating nanopores in the top surface of YSZ for use in functional surfaces without serious thermal damage to the workpiece. It is expected that the nanopore generation will lead to new applications of YSZ.

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Significant improvement in surface hardness of Zr-based metallic glass by nanosecond pulsed laser irradiation in graphite powder water suspension

Zhang H., Qian Y., Zhang L., Jiang M., Huang H., Yan J.

Surface and Coatings Technology (Surface and Coatings Technology) 454 2023.02

ISSN 02578972

Metallic glasses (MGs) have shown promising application prospects as structural materials due to their unique mechanical properties. While, for broadening their application as functional materials, significant improvement in surface hardness of MGs is required. Accordingly, in this study, laser carbonization of MGs was attempted by irradiating the Zr-based MG surface immersed in graphite powder water suspension using a nanosecond pulsed laser. Nanoindentation response and surface morphologies of the initial and irradiated surfaces were characterized in detail. The results indicated that the hardness of the laser-irradiated surfaces was increased by 130 %–200 % (from 6.407 GPa to 19.193 GPa), and as well, the serrated flows in load-depth curves and the surface shear bands around the residual indent disappeared, suggesting the change in micro-scale plastic deformation behaviors of the laser-irradiated surfaces. Furthermore, the chemical composition of the initial and irradiated surfaces was analyzed by X-ray diffraction (XRD) and energy dispersive spectrometer (EDS), which showed that the irradiated surfaces were carbonized in the graphite powder water suspension. Accordingly, the increase in surface hardness was due to the formation of the hard crystalline phases.

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Repairing surface defects of Zr-based metallic glass ribbons by nanosecond pulsed laser irradiation

Wang J., Zhang H., Zhang Z., Hong J., Qian Y., Huang H., Yan J.

Manufacturing Letters (Manufacturing Letters) 35 48 - 52 2023.01

ISSN 22138463

The metallic glass ribbons (MGRs) industrially produced by the single roller melt-spun method have many surface defects such as pits and scratches. In this study, it was attempted to repair the surface defects of Zr-based MGRs via nanosecond pulsed laser irradiation. The experimental results showed that the roughness of laser-repaired surfaces was significantly reduced compared to the melt-spun surface, and the surface topographies and morphologies were sensitive to the laser parameters. With optimal laser parameters, the smooth and defect-free surface could be achieved. This work offers a convenient and high-efficiency approach for repairing the surface defects of MGRs.

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Life-cycle assessment of the laser sintered-silicon anode for lithium ion battery production

Hendrickx B., Yan J., Duflou J.

Procedia CIRP (Procedia CIRP) 116 594 - 599 2023

ISSN 22128271

As the global market for lithium-ion batteries continues to grow, sourcing alternative materials for battery cell production gains interest and has an ever increasing potential to reduce environmental impact during the production phase. Around 97% of the produced Li-ion batteries contain a graphite-based anode, coated on a copper foil. In this Life Cycle Assessment the potential reduction of environmental impact over various categories during the production of batteries when using an anode production method by laser sintering Si-waste powder in an innovative process is investigated. The study provides an indication of environmental feasibility of the suggested production process, comparing the technical innovative process to currently available anode production processes. The impact comparison is made on the level of anode production (cradle to gate) with the potential to zoom out to the full battery production process in future work. Current results indicate that the overall impact of production increases 27% when using the suggested anode production process, with the results being sensitive to the amount of energy required for sintering and the allocation of impact towards the Si-waste. The impact of this switch of anode production method for the full Li-ion battery production will depend on the affected charge capacity and lifetime duration of an assembled battery module.

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Nanosecond Laser “Pulling” Patterning of Micro–Nano Structures on Zr-Based Metallic Glass

Cui M., Huang H., Zhang L., Yan J.

Small (Small) 19 ( 14 ) 2023

ISSN 16136810

Flexible and controllable fabrication of micro–nano structures on metallic glasses (MGs) endow them with more functional applications, but it is still challenging due to the unique mechanical, physical, and chemical properties of MGs. In this study, inspired by a new physical phenomenon observed in the nanosecond laser–MG interaction (i.e., the surface structure is transformed from the normally observed microgroove into the micro–nano bulge at a critical peak laser power intensity), a nanosecond laser “pulling” method is proposed to pattern the MG surface. The formation mechanism and evolution of the micro–nano bulge are investigated in detail, and accordingly, various micro–nano structures including the unidirectional stripe, pillar, cross-hatch patterns, “JLU”, circle, triangle, and square, are derived and created on the MG surface, which affects the surface optical diffraction. Overall, this study provides a highly flexible and controllable method to fabricate micro–nano structures on MGs.

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Fabrication and functional characteristics of micro/nano structures on the RB-SiC surface through nanosecond pulsed laser irradiation

An H., Qian Y., Zhang L., Zhang Z., Huang H., Yan J.

Ceramics International (Ceramics International) 49 ( 22 ) 36276 - 36288 2023

ISSN 02728842

Reaction-bonded silicon carbide (RB-SiC) is gaining increasing attention due to its exceptional mechanical properties contributed by the dispersion of hard silicon carbide (SiC) and silicon (Si), which has been extensively applied in aerospace and automobile industries. Fabrication of micro/nano structures on the RB-SiC surface can endow it some specific functional properties, but conventional manufacturing procedures face challenges due to the intrinsic hard-brittle nature of RB-SiC. In the present study, various micro/nano structures, including dome-like particle structures, micro-cone structures and the spider web-like film, are fabricated on the RB-SiC surface by nanosecond pulsed laser irradiation under different experimental conditions. Comparative experiments are performed to explore the effects of laser power and scanning speed on the microscopic morphology and chemical composition. Consequently, the ablation mechanism is clarified. The formation of micro-cone structures covered by the spider web-like film can result in a wettability transition of the RB-SiC surface from hydrophilicity to superhydrophilicity. In addition, by introducing the spider web-like film, the reflectivity of the RB-SiC surface is increased by an impressive 83% or more in the wavelength range of 200 to 2500 nm. This study provides a method for improving the surface properties of RB-SiC substrates using a laser-based approach, which is anticipated to expand their application prospects as functional materials.

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Effects of process parameters on cutting forces, material removal rate, and specific energy in trochoidal milling

Wagih M., Hassan M.A., El-Hofy H., Yan J., Maher I.

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science (Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science) 238 ( 7 ) 2745 - 2757 2023

ISSN 09544062

Trochoidal milling has been developed to enhance tool life during slot machining. It is characterized by reduced cutting forces, cutting temperature, and tool wear as compared to conventional milling processes. It is effective in machining difficult-to-cut materials, high-speed machining, and groove corners. However, this process has not been deeply investigated enough to discover its advantages and optimize its parameters. A full factorial design of 144 experiments has been applied in this paper to investigate extensively the effects of axial depth of cut, feed rate, and trochoidal step on material removal rate, cutting forces, and specific energy in trochoidal milling. Trochoidal step and axial depth of cut almost have the same contributions on cutting forces by 32% and 31% respectively, followed by feed rate by 25%. Feed rate, trochoidal step, and axial depth of cut influence the material removal rate by 37%, 30%, and by 19% respectively. The contributions of feed rate, trochoidal step, and axial depth of cut on relative specific energy are 57%, 24%, and 8% respectively. The increase of axial depth of cut increases the maximum resultant force till a threshold value, then it stabilizes. This behavior occurred due to the increase of the maximum engagement angle to a certain limit, then it does not increase any more. Both feed rate and trochoidal step linear affect maximum resultant force and material removal rate, while the relationships are non-linear for specific energy. It is recommended to machine slots in full depth with the highest possible trochoidal step and feed rate, considering the increase of tool wear and surface roughness. It is preferred to use a cutting tool of a large helix angle and small diameter to reduce the threshold axial depth of cut. Overall, this study is significant in characterizing, designing, and optimizing of trochoidal milling through experimental work.

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Effect of tool geometry on ultraprecision machining of soft-brittle materials: A comprehensive review

Huang W., Yan J.

International Journal of Extreme Manufacturing (International Journal of Extreme Manufacturing) 5 ( 1 ) 2022.12

ISSN 26318644

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Design and fabrication of micro and nano surface structures for enhancing metal–polymer adhesion using femtosecond laser treatment

Omiya M., Nakajima A., Yan J.

Materials and Design (Materials and Design) 224 2022.12

ISSN 02641275

This study investigated the effects of micro- and nanostructures on the adhesion strength between copper and an encapsulating mold compound (EMC). The shape of the microgrooves was designed based on fracture mechanics theory, and the effect of laser-induced periodic structure surface (LIPSS) formation on the microgroove was investigated using numerical simulations. The designed surface profiles were fabricated using femtosecond laser treatments, and the adhesion strength between copper and the EMC was evaluated. The results show that deep microgrooves improved the adhesion strength owing to the anchor effect. However, the aspect ratio between the pitch and depth of the microgroove had a limitation in enhancing the adhesion strength. The formation of LIPSSs on the mountaintop of the microgroove was very effective; however, an LIPSS on the valley of the microgroove was ineffective. Numerical analyses revealed that LIPSSs suppressed the shear deformation of the EMC and worked as resistance to interface delamination. Based on the findings obtained in this study, combining micro- and nano-scale surface structure formation with femtosecond laser treatments is an effective and eco-friendly method for improving adhesion strength.

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What micro-mechanical testing can reveal about machining processes

Axinte D., Huang H., Yan J., Liao Z.

International Journal of Machine Tools and Manufacture (International Journal of Machine Tools and Manufacture) 183 2022.12

ISSN 08906955

For many years, the machining community has dedicated significant efforts to investigate the microscopic scale level phenomena during the material removal process. On one hand much research has been carried out in relation to workpiece surface integrity after machining and the methods for its study. On the other hand, many studies have been dedicated to replicate machining conditions at microscopic scales using high resolution setups. Although these two topics seem to be little related, there is an opportunity of the machining community to take the advantage of the advanced testing/investigation setups that enable these two strands of research to be performed at very high resolution and repeatability, thus giving new pathways for research in this field. Here we are flagging up to the community the research opportunities offered by micro-mechanical testing that can be performed using in-situ scanning electron microscopes (SEM) or other high-resolution imaging instruments. As such, this review paper discusses the recent research advances in using in-situ micro-mechanical testing for: (i) understanding the phenomena occurring in the workpiece (sub) surfaces after machining operation by performing very high resolution micro-mechanical testing (e.g. compression/bending of micro-pillars/beams) within particular zones of machined superficial layers; (ii) studying the material removal mechanisms at micrometric level using common indenters or dedicated edges to understand how the workpiece materials (e.g. groups/single grains) react to cutting conditions. Finally, we comment on possible future research topics using micro-mechanical testing in-situ in high resolution imaging instruments and how this could help to advance the understanding of machining processes.

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Investigating the Combined Effect of Multiple Dent and Bump Faults on the Vibrational Behavior of Ball Bearings

Atef Mahmoud M., Khair-Eldeen Wael, Yan Jiwang, Nassef Mohamed G. A.

Machines (Machines) 10 ( 11 ) 2022.11

The rolling element bearing is a fundamental component of any rotating machinery. During operation, wear debris and lubricant impurities create dents and bumps on the bearing raceway surfaces. Such localized defects produce transient vibration impulses at one of the bearing characteristic frequencies. Having a combination of multiple types of point defects on the raceway results in superimposed vibration patterns, which reduce the ability to recognize these defects’ effects. In this paper, a 6-DOF dynamic model is developed to accurately investigate the vibration characteristic of a ball bearing with a multipoint defect comprising a dent and bump on its raceway surface. The model considers the effects of time-varying contact force produced due to defects, lubricant film damping, bearing preload, and the inertia effect of rolling elements. The simulation results reveal the vibration behavior of multipoint defect bearings. In addition, bearing vibration response is affected by the number of defects, the angle between them, and the type and size of each defect. Furthermore, it is challenging to predict bearing defects parameters such as the numbers, types, sizes, and angles between adjacent defects from acceleration signal analysis without jerk signal analysis. The validation of the model is proved using signals from the Case Western University test setup.

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Surface hardening of Zr-based metallic glass via laser surface alloying with silicon powder

Zhang D., Qian Y., Zhang L., Huang H., Yan J.

Scripta Materialia (Scripta Materialia) 220 2022.11

ISSN 13596462

Increasing the hardness and wear resistance of metallic glasses (MGs) is beneficial to prolong their service life in highly aggressive environments. For the purpose of achieving surface hardening, in this work, laser surface alloying technology was employed to modify Zr-based MG with silicon powder as the pre-placed powder. The experimental results showed that the laser alloyed layer with thickness of several tens of micrometers was generated on the MG substrate. The surface hardness of the laser alloyed layers ranged from 11.34 to 17.97 GPa, which was significantly higher than that of the as-cast MG surface (6.36 GPa). Furthermore, the scratch resistance of the laser alloyed layer was improved compared to the as-cast sample. The chemical composition analysis indicated that the laser alloyed layer was mainly composed of in-situ formed ZrSi2 phase and residual Si, and these hard phases were responsible for the high hardness of the laser alloyed layer.

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Formation, evolution and characterization of nanoporous structures on the Ti6Al4V surface induced by nanosecond pulse laser irradiation

Wang C., Huang H., Zhang Z., Zhang L., Yan J., Ren L.

Materials and Design (Materials and Design) 223 2022.11

ISSN 02641275

Manipulating materials at nanoscale is challenging but rewarding. Nanostructures exhibit some unique properties distinguished from macroscopic bulk materials, so fabrication of nanostructures on the material surface is beneficial to broaden their functional applications. In this study, by nanosecond pulse laser irradiation in nitrogen atmosphere, it was found that unique nanoporous structures could be formed on the Ti6Al4V surface. The effects of laser parameters including the laser power, overlap rate, scanning speed, and repetition frequency on the formation and evolution of the nanoporous structures were systematically investigated. By changing the laser parameters, the nanoporous structures with various porosities could be easily achieved on the Ti6Al4V surface. According to the structural evolution and chemical composition, the formation mechanism of the nanoporous structures was discussed. Furthermore, by characterizing the micro-mechanical properties and wettability, it was found that the surface with nanoporous structures exhibited similar surface hardness but improved tribological performances compared to the original Ti6Al4V surface, and the surface wettability could be tuned. This study provides a simple method for fabricating nanoporous structures on the Ti6Al4V surface, which would broaden its functional applications.

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Study on nano-graphitic carbon coating on Si mold insert for precision glass molding

Zhang L., Yan J.

Surface and Coatings Technology (Surface and Coatings Technology) 448 2022.10

ISSN 02578972

Precision glass molding is an efficient and promising technique for large-volume micro-optical manufacturing. Even though significant progress in precision glass molding has been achieved on the anti-adhesive coating, technical challenges and barriers still exist towards tailoring the coating layer to ensure durability and long-term processing consistency in numerous molding cycles. This manuscript presents a novel molding technique utilizing micro-patterned Si mold inserts coated with a newly developed nano-graphitic carbon coating as an isolation layer in high-precision glass molding. The coating is prepared by atmospheric pressure chemical vapor deposition (APCVD), in which the liquid benzene and silicone rubber are used as the carbon source and silicon oxycarbide (SiOC) source, respectively. The nano-morphologies of the nano-graphitic carbon coating with different conditions are characterized and analyzed, illustrating notable differences in surface features with the addition of silicone rubber and various growth durations. In the demonstration, the nano-graphitic carbon-coated Si mold inserts exhibit unique properties, including anti-adhesive and hydrophobic at elevated temperatures. Two kinds of micro-patterned Si mold inserts, a micro-pillar matrix and a micro-lens array, generated by UV lithography and diamond turning, are utilized to demonstrate the feasibility of the anti-adhesive coating in precision glass molding. The obtained results indicate that the micro-optical features on the coated Si mold inserts are successfully transferred to glass substrates with high replication fidelity without notable signs of adhesion or contamination in repetitive molding cycles. This emerging technology makes Si an alternative mold material with low surface adhesion, enhances micro-optical machining efficiency, and replicates high-precision, low-cost micro-optics on large scales that were previously unavailable.

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On the conversion of point-to-linear hierarchical micro/nano-structures on the glassy carbon surface by nanosecond pulsed laser irradiation

Wang C., Zhang H., Huang H., Zhang Z., Zhang L., Yan J.

Applied Surface Science (Applied Surface Science) 599 2022.10

ISSN 01694332

Fabrication of microstructures on the glassy carbon (GC) surface is crucial for its functional applications. However, due to its intrinsic mechanical, physical, and chemical properties, it is still challenging to fabricate hierarchical micro/nano-structures on the GC surface. In this study, by tuning the interval between adjacent points as well as the irradiation time, the conversion from the point to linear hierarchical micro/nano-structures was successfully achieved on the GC surface by nanosecond pulsed laser irradiation. The detailed conversion process and mechanism were explored and discussed. On this basis, the linear hierarchical micro/nano-structures were fabricated by direct line scanning, and the internal nanostructures were always parallel to the laser scanning direction. By repeated line scanning with relatively low laser fluence, the method of direct line scanning was further improved, and well-defined and uniform hierarchical micro/nano-structures were fabricated.

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Towards understanding the mechanism of vibration-assisted cutting of monocrystalline silicon by cyclic nanoindentation

Huang W., Yan J.

Journal of Materials Processing Technology (Journal of Materials Processing Technology) 311 2022.10

ISSN 09240136

Ultrasonic vibration cutting (UVC) is a promising technology that can promote the processing of hard-brittle materials in ductile mode. The feature of intermittent cutting in UVC is considered to promote the ductile responses of brittle materials. However, the effect of cyclic loading/impact on microscopic deformation behavior of the workpiece material in UVC is not clearly understood. This study used cyclic nanoindentation to reveal the UVC mechanism in monocrystalline silicon (Si). The surface morphology and subsurface microstructure of the residual indents were characterized and compared with those of the UVC-machined grooves. This work attempted to correlate the tool-workpiece contacts for cyclic nanoindentation and vibration cutting. Cyclic nanoindentation results show that cyclic loading promotes the extent of silicon amorphization and decreases the threshold for transitioning the β–Sn phase to the bc8 and r8 phases. As the number of indentation cycles increases, the subsurface microstructure changes from the amorphous phase to the bc8 and r8 phases. In UVC, both the critical cutting depth for brittle-to-ductile transition and the degree of amorphization in cutting chips increase in comparison to conventional cutting, which matches the trend of cyclic nanoindentation results. The findings inform the chip formation and subsurface deformation mechanisms of brittle materials during UVC.

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Microstructure and mechanical properties of SiC particle reinforced Zr-based metallic glass surface composite layers produced by laser alloying

Qian Y., Zhang D., Hong J., Zhang L., Jiang M., Huang H., Yan J.

Surface and Coatings Technology (Surface and Coatings Technology) 446 2022.09

ISSN 02578972

Metallic glasses (MGs) are a promising candidate for advanced structural applications due to their superior mechanical properties. Improving their surface mechanical properties would be of great importance for promoting their structural and functional applications. In this study, SiC particles were used as the reinforcement to improve the mechanical properties of Zr-based MG via laser surface alloying. The influences of the average laser power and overlap ratio between neighboring laser processing lines on the microstructure and mechanical properties of the laser-alloyed surface layer were investigated. The experimental results indicated that ZrC and SiC phases were successfully introduced into the MG matrix by laser surface alloying, and the content of these two hard ceramic phases was dependent on the laser processing parameters. The formed laser-alloyed surface layers exhibited a significant improvement in overall hardness compared with the as-cast specimen. At a relatively high overlap ratio of 70%, the average hardness of the MG matrix within the laser-alloyed surface layer reached 28.91 GPa, which was three times higher than that of the as-cast specimen (6.46 GPa). Furthermore, the microstructural characteristics and mechanical properties of the cross-sections of the laser-alloyed samples were characterized. The thickness of the laser-alloyed surface layer reached several tens of microns, and the SiC particles were uniformly dispersed in the whole laser-alloyed surface layer. This study confirms the feasibility for improving the mechanical properties of MGs by laser surface alloying, which is expected to broaden the application of MGs as structural and functional components under harsh severe conditions.

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Achieving Superhydrophobicity of Zr-Based Metallic Glass Surfaces with Tunable Adhesion by Nanosecond Laser Ablation and Annealing

Cui M., Huang H., Wang C., Zhang L., Yan J.

ACS Applied Materials and Interfaces (ACS Applied Materials and Interfaces) 14 ( 34 ) 39567 - 39576 2022.08

ISSN 19448244

Tuning the surface wettability and adhesion of metallic glasses (MGs) is a promising approach to enrich their engineering applications. In this study, using nanosecond laser ablation in air, hierarchical micro/nanostructures were directly fabricated on a Zr-based MG surface. Following subsequent annealing, the surface exhibited superhydrophobicity (maximum contact angle: 166°, minimum sliding angle: 2°). Furthermore, the superhydrophobic surface could be tuned from low to high surface adhesion force by controlling the laser-ablated spot interval. By analyzing the laser-ablated structures and surface chemical compositions, the superhydrophobicity was related to the formation of hierarchical micro/nanostructures and the absorption of organic compounds with low surface free energy in air, and the change in surface adhesion force was attributed to the difference in surface roughness. The experimental results showed that the superhydrophobic surface with low adhesion force could be used in self-cleaning applications, while the superhydrophobic surfaces with different adhesion forces could be used in no-loss liquid transportation. This study provides an efficient and low-cost way to fabricate superhydrophobic MG surfaces with tunable adhesion, which will broaden the functional applications of MGs.

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Visualization of indentation induced sub-surface shear bands of Zr-based metallic glass by nanosecond pulse laser irradiation

Cui M., Huang H., Wang C., Qian Y., Zhang L., Zhang Z., Yan J.

Vacuum (Vacuum) 202 2022.08

ISSN 0042207X

Characterizing the shear band of metallic glasses (MGs) is meaningful to understand its plastic deformation mechanism. However, the direct method for detecting the internal shear bands of deformed MGs with large field of view is still lacking. Inspired by the fact that surface defects have the enhanced absorption of laser energy, this study attempted to visualize the indentation induced sub-surface shear bands of Zr-based MG by nanosecond pulse laser irradiation in argon. The principle was first verified by laser irradiation of the surface scratch, and then implemented on the visualization of sub-surface shear bands. The experimental results demonstrated that the indentation induced sub-surface shear bands were successfully visualized by nanosecond pulse laser irradiation, and meanwhile, the laser irradiated surface maintained the amorphous characteristic. This study may open a new window for exploring the shear band characteristics of MGs upon external loads.

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Direct Observation of Discharge Phenomena in Vibration-Assisted Micro EDM of Array Structures

Esser G., Yan J.

Micromachines (Micromachines) 13 ( 8 ) 2022.08

The batch mode electrical discharge machining (EDM) method has been developed to improve the throughput and accuracy in fabricating array structures, but the process suffers from insufficient debris removal caused by the complex electrode geometry. Tool vibration has been used to improve flushing conditions, but to date the underlying mechanism of the tool vibration on the micro EDM of array structures remains unclear. This study aimed to investigate the effect of tool vibration on the machining process by direct observation of the discharge phenomena in the discharge gap by using a high-speed camera. Micro EDM experiments using 9 and 25 array electrodes were performed, and the effect of tool vibration on the discharge uniformity and tool wear was evaluated. It was found that tool vibration improved the uniformity of the discharge distribution, increased the machining efficiency, and suppressed the tool wear. The discharges occurred in periodic intervals, and the intensity increased with the amplitude of tool vibration. The results of this study indicate that the vibration parameters determine the discharge period duration and intensity to achieve optimum stability and efficiency of the machining process.

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A novel method for fabricating micro-dimple arrays with good surface quality on metallic glass substrate by combining laser irradiation and mechanical polishing under wax sealing

Huang H., Qian Y., Zhang L., Jiang M., Yan J.

Journal of Manufacturing Processes (Journal of Manufacturing Processes) 79 911 - 923 2022.07

ISSN 15266125

Surface micro-patterning is an emerging technique to endow a wide range of materials with specific functions, such as superhydrophobicity and anti-reflection, but it is still technically challenging and inordinately expensive via existing manufacturing approaches. Compared with crystalline metals, metallic glasses (MGs) are talented with some unique mechanical and chemical properties due to their isotropic internal structure. Here, a novel two-step method, involving nanosecond pulsed laser irradiation and mechanical polishing, was proposed to fabricate micro-dimple arrays with good surface quality on the MG substrate. In the first step, multi-pulse laser irradiation experiments were performed to study the correlation between the peak laser power intensity and the feature sizes of the micro-dimple (i.e. the depth and diameter of the micro-dimple as well as the height of the pile-up), and then various micro-dimple arrays were fabricated on the MG substrate by adjusting the peak laser power intensity and the interval between adjacent laser shots. Subsequently, aiming at improving the surface quality, the micro-dimple arrays were mechanically polished under wax sealing. The experimental results indicated that after polishing, the pile-ups around the micro-dimples were completely removed, and at the same time, the surface quality of their inner walls was improved. Furthermore, based on experimental results, the possible material removal mechanism during polishing was discussed. This study provides a convenient method to fabricate micro-dimple arrays with good surface quality on the MG substrate, which would be one of the potential alternatives for large-area, low-cost micro/nano-manufacturing.

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Nanometric cutting: Mechanisms, practices and future perspectives

Fang F., Lai M., Wang J., Luo X., Yan J., Yan Y.

International Journal of Machine Tools and Manufacture (International Journal of Machine Tools and Manufacture) 178 2022.07

ISSN 08906955

Nanometric cutting removes material at nanoscale and generates high-quality surfaces with a nanometric finish. In past decades, it has thrived as a mainstream manufacturing technology to produce critical components to advance scientific discovery and promote innovation in various fields, such as astronomy, aerospace, microelectronics, optics and photonics, biology and quantum technology. Therefore, it is timely to develop a review article capturing such developments and establishing directions for future advancement. This article systematically reviews the fundamental issues such as cutting model, material deformation mechanism and tool wear in nanometric cutting. It also presents the working principles of innovative ion implantation-assisted, laser-assisted and ultrasonic vibration-assisted nanometric cutting methods to overcome the challenges of machining difficult-to-cut materials. Practical techniques for the generation of high-quality complex or structured surfaces are also discussed. Finally, challenges and future perspectives of nanometric cutting, as well as the evolution towards atomic and close-to-atomic scale manufacturing, are outlined.

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Micro Electrical Discharge Machining of Ultrafine Particle Type Tungsten Carbide Using Dielectrics Mixed with Various Powders

Sai Dutta Gattu and Jiwang Yan

Micromachines ({MDPI} {AG}) 13 ( 7 ) 998 2022.06

Electrical discharge machining (EDM) is widely used to machine hard materials, such as tungsten carbide; however, the machining rate and surface quality are low. In this research, the effects of mixing electrically conductive carbon nanofiber (CnF), semiconductive silicon (Si) powder, and insulative alumina powder (Al2O3) at different concentrations in a dielectric fluid were studied by observing single discharge craters and hole machining performance in the EDM of ultrafine particle type tungsten carbide. Craters obtained using carbon nanofiber and alumina were much smaller than in oil-only conditions. In contrast, The results show that adding CnF significantly improved the material removal rate under all conditions. Si and Al2O3 powders only improved the machining performance at a high discharge energy of 110 V. Furthermore, improvement in surface roughness was observed prominently at high voltages for all the powders. Among the three powders, alumina was found to improve the surface roughness the most.

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Crack Propagation Behavior of Fused Silica during Cyclic Indentation under Incremental Loads

Kosai K., Zhao Y., Yan J.

Applied Sciences (Applied Sciences (Switzerland)) 12 ( 13 ) 2022.06

Fused silica is an important optical material with important applications, where the surface must be precisely machined without subsurface damage. In this study, multi-cyclic indentations under incremental loads were performed on fused silica using two kinds of indenters to clarify the mechanisms of crack generation and propagation induced by precision grinding. It was found that incremental loading cyclic nanoindentation induced various patterns of subsurface cracking and surface spalling. Four kinds of surface spalling were identified at different locations around an indent, the temporal formation mechanisms of which were clarified by microscopic observation and topographical measurement. Load–displacement curve analysis demonstrated that incremental propagation of lateral cracks during early indentation cycles caused large-scale brittle fractures during later cycles. Compared with a Berkovich indenter, a cube-corner indenter caused more significant brittle fractures and surface spalling. The findings in this study will deepen the understanding of subsurface damaging mechanism of fused silica and other brittle solids caused by cyclic tool-workpiece interactions in grinding and other mechanical machining processes.

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Microstructures and mechanical properties of Zr-based metallic glass ablated by nanosecond pulsed laser in various gas atmospheres

Y Qian, M Jiang, Z Zhang, H Huang, J Hong, J Yan

Journal of Alloys and Compounds, 163717 (Journal of Alloys and Compounds) 901 2022.04

ISSN 09258388

The surface with micro-convex prepared by laser ablation is beneficial to improving the functional properties of metallic glasses (MGs). However, accompanied by the formation of micro-convex, surface hardness of the ablated area generally decreases due to the softening effect caused by laser thermal shock. Previous studies have shown that the mechanical properties of laser-ablated MG surface are significantly different when using different gas atmospheres. In this study, a comparative investigation was performed to analyze the influence of gas atmosphere (i.e. argon, nitrogen, and air) on the formation of micro-convex as well as its surface characteristics and mechanical properties. Experimental results showed that the atmosphere type did not affect the formation of micro-convex, but significantly affected the surface morphology and element composition of the laser-ablated area. The element analysis and Raman spectral measurements indicated that laser ablation in nitrogen or air atmosphere resulted in local nitridation or oxidation. The results of nanoindentation tests demonstrated that laser ablation in nitrogen or air atmosphere also resulted in surface hardness inhomogeneity, i.e., softening and hardening effects coexist in the ablated area, which could be attributed to the combined influence of laser thermal shock, the introduction of secondary phase as well as laser ablation induced loose structure.

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Tool Path Generation and Optimization for Freeform Surface Diamond Turning Based on an Independently Controlled Fast Tool Servo

Y Sato, J Yan

International Journal of Extreme Manufacturing (International Journal of Extreme Manufacturing) 4 ( 2 ) 025102 2022.03

ISSN 26318644

Diamond turning based on a fast tool servo (FTS) is widely used in freeform optics fabrication due to its high accuracy and machining efficiency. As a new trend, recently developed high-frequency and long-stroke FTS units are independently driven by a separate control system from the machine tool controller. However, the tool path generation strategy for the independently controlled FTS is far from complete. This study aims to establish methods for optimizing tool path for the independent control FTS to reduce form errors in a single step of machining. Different from the conventional integrated FTS control system, where control points are distributed in a spiral pattern, in this study, the tool path for the independent FTS controller is generated by the ring method and the mesh method, respectively. The machined surface profile is predicted by simulation and the parameters for the control point generation are optimized by minimizing the deviation between the predicted and the designed surfaces. To demonstrate the feasibility of the proposed tool path generation strategies, cutting tests of a two-dimensional sinewave and a micro-lens array were conducted and the results were compared. As a result, after tool path optimization, the peak-to-valley form error of the machined surface was reduced from 429 nm to 56 nm for the two-dimensional sinewave by using the ring method, and from 191 nm to 103 nm for the micro-lens array by using the mesh method, respectively.

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Generation of Si@ C/SiC@ C core–shell nanoparticles by laser irradiation of silicon grinding waste

K Minami, K Kobinata, J Yan

Nano Select (Wiley) 3 ( 7 ) 1192 - 1200 2022.03

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Flexible fabrication of fresnel micro-lens array by off-spindle-axis diamond turning and precision glass molding

L Zhang, YY Allen, J Yan

Precision Engineering (Elsevier {BV}) 74 186 - 194 2022.03

Research paper (scientific journal), Joint Work, Accepted, ISSN 01416359

Fresnel micro-lens arrays with close-to-wavelength features have significant advantages in minimization of optical systems. However, in the fabrication of a Fresnel micro-lens array by conventional diamond turning, the discontinuous features of the surface profile cause interference between the tool flank face and the finished surface. In this manuscript, a novel off-spindle-axis diamond turning method is proposed to fabricate Fresnel micro-lens array mold insert and a toolpath generation algorithm is developed. The generation of each lenslet is treated as an independent turning operation, and the whole fabrication of a Fresnel micro-lens array is completed by a succession of repetitive turning operations. With this approach, the interference between the tool and the finished surface is avoided, and the form accuracy and surface integrity are improved for each lenslet. Then, the Fresnel micro-lens array mold insert is further utilized in precision glass molding to replicate the micro-lens structures onto transparent polymer substrates. The experimental results indicate that both the diamond-turned and molded Fresnel micro-lens arrays are achieved with homogeneous quality. As an application, a compact imaging system based on the molded Fresnel micro-lens array is demonstrated. The proposed machining method in this study can be employed in the fabrication of Fresnel micro-lens arrays and other micro-optics with discontinuous profiles with high accuracy and machining efficiency.

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Development of High-Sensitivity Electrically Conductive Composite Elements by Press Molding of Polymer and Carbon Nanofibers

S Aikawa, Y Zhao, J Yan

Micromachines 13 (2), 170 ({MDPI} {AG}) 13 ( 2 ) 170 2022.01

Research paper (scientific journal), Joint Work, Accepted

Carbon nanofibers (CNFs) have various excellent properties, such as high tensile strength, electric conductivity and current density resistance, and thus have great application potential in electrical sensor development. In this research, electrically conductive composite elements using CNFs sandwiched by thermoplastic olefin (TPO) substrates were developed by press molding. The metal mold used for press molding was processed by a femtosecond laser to generate laser-induced periodic surface structures (LIPSS) on the mold surface. The aggregate of CNFs was then flexibly fixed by the LIPSSs imprinted on the TPO substrate surface to produce a wavy conductive path of CNFs. The developed composite elements exhibited a sharp increase in electrical resistance as strain increased. A high gauge factor of over 47 was achieved, which demonstrates high sensitivity against strain when the composite element is used as a strain gauge. Scanning electron microscope observation revealed that the TPO filled the spaces in the aggregate of CNFs after press molding, and the conductive path was extended by the tensile strain. The strain-induced dynamic changes of contact states of CNFs and CNFs networks are discussed based on the electrical performance measurement and cross-sectional observation of the elements. This research provides a new approach to the production of flexible and high sensitivity strain sensors.

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Nitrogen assisted formation of large-area ripples on Ti6Al4V surface by nanosecond pulse laser irradiation

C Wang, H Huang, Y Qian, Z Zhang, W Huang, J Yan

Precision Engineering (Elsevier {BV}) 73 244 - 256 2022.01

ISSN 0141-6359

Ti6Al4V is one of the most widely used titanium alloys due to its excellent mechanical, physical, and chemical properties. Laser surface texturing is a promising method to endow new functions of material surfaces; however, direct generation of laser-induced periodic surface structure (LIPSS) on the Ti6Al4V surface by nanosecond laser is rarely reported. In this study, by nanosecond laser irradiation in nitrogen atmosphere, the ripples (a typical LIPSS) were directly fabricated on the Ti6Al4V surface. By single-line laser scanning, the effects of laser irradiation parameters including the laser power and repetition frequency on the formation and evolution of the ripples were systematically investigated, followed by optimizing the laser irradiation parameters to achieve the large-area regular and clear ripples with relatively good surface quality as well. Furthermore, by performing contrast experiments in argon atmosphere, the role of nitrogen atmosphere on the formation of ripples was confirmed. Accordingly, formation mechanism of the ripples was discussed. Finally, the effects of the formed ripples on the surface color and wettability were preliminarily characterized to demonstrate the potential applications of surface ripples. This paper provides a nitrogen assisted method to fabricate large-area ripples on the Ti6Al4V surface by nanosecond laser irradiation.

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The effects of simultaneous laser nitriding and texturing on surface hardness and tribological properties of Ti6Al4V

C Wang, J Hong, M Cui, H Huang, L Zhang, J Yan

Surface and Coatings Technology, 128358 (Surface and Coatings Technology) 437 2022

ISSN 02578972

The low hardness and poor tribological properties of titanium and its alloys significantly hinder their practical engineering applications, so surface nitriding or texturing is widely employed to improve the surface performances. However, previous studies mainly used the single method (surface nitriding or texturing), and simultaneous nitriding and texturing are rarely reported. Therefore, their combined effects on the surface mechanical and tribological properties are rarely investigated as well. In this study, by nanosecond pulse laser irradiation in nitrogen atmosphere, simultaneous nitriding and texturing of the Ti6Al4V surface were achieved. The effects of laser parameters including laser power, laser overlap rate, and number of scanning cycles, on the surface hardness and tribological properties of laser irradiated surfaces were comparatively studied. The experimental results showed that after simultaneous laser nitriding and texturing, the surface hardness of Ti6Al4V surface was increased by 50%~95%, and the coefficient of friction (COF) was reduced by 70%~80%. Furthermore, the laser processed surfaces obtained under various irradiation parameters presented quite different scratching characteristics, and the corresponding deformation mechanisms during scratching were analyzed. This study provides a simple and effective method by simultaneous laser nitriding and texturing for improving the surface properties of Ti6Al4V, which would be meaningful for its practical engineering applications.

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Generation of micro/nano hybrid surface structures on copper by femtosecond pulsed laser irradiation

Nakajima A., Omiya M., Yan J.

Nanomanufacturing and Metrology (Nanomanufacturing and Metrology) 5 ( 3 ) 274 - 282 2022

ISSN 2520811X

The delamination of copper lead frames from epoxy molding compounds (EMC) is a severe problem for microelectronic devices, as it leads to reduced heat dissipation or circuit breakage. The micro/nanoscale surface structuring of copper is a promising method to improve the copper–EMC interfacial adhesion. In this study, the generation of micro/nano hybrid structures on copper surfaces through femtosecond pulsed laser irradiation is proposed to improve interfacial adhesion. The micro/nano hybrid structures were realized by generating nanoscale laser-induced periodic surface structures (LIPSS) on microscale parallel grooves. Several types of hybrid surface structures were generated by changing the laser polarization direction, fluence, and scanning speed. At a specific aspect ratio of microgrooves, a latticed structure was generated on the sides of microgrooves by combining LIPSS formation and direct laser interference patterning. This study provides an efficient method for the micro/nanoscale hybrid surface structure formation for interfacial adhesion improvement between copper and EMC.

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Exploratory investigation of chip formation and surface integrity in ultra-high-speed gear hobbing

Ueda Y., Sakurai N., Takagi T., Ishizu K., Yan J.

CIRP Annals (CIRP Annals) 71 ( 1 ) 89 - 92 2022

ISSN 00078506

Gear hobbing is widely employed to manufacture automotive gears, where the productivity depends on the cutting speed. Currently, gear hobbing is performed at ∼300 m/min using high-speed steel hob cutters. In this study, ultra-high-speed gear hobbing was attempted using a large-diameter cemented carbide hob cutter on a gear grinder. This enabled a cutting speed up to 2450 m/min. Many interesting phenomena were acquired in this speed range. Chips were severely oxidized, whereas the gear surface was not affected. Compressive residual stress was generated at the gear surfaces with low surface roughness and high hardness, while the wear of hob cutter was insignificant.

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Dynamic modeling and in-process parametric compensation for fabricating micro straight thin walls by micromilling

Li Yang, Cheng Xiang, Zheng Guangming, Yan Jiwang, Liu Huanbao, Li Xuewei

JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T (Journal of Materials Research and Technology) 18 2480 - 2493 2022

ISSN 2238-7854

A comprehensive dynamic model is introduced try to further reduce dimensional errors of micromilled micro straight thin walls based on an in-process cutting parameter compensation device. First, a mathematical model is established to predict the dynamic elastic deformation of the thin walls in the micromilling process. Next, the radial deformation and the runout of the cutter are modeled. Then, the comprehensive in-process parametric compensation model and strategy are established. Finally, a real-time in-process cutting force measurement and cutting parameter compensation device is applied to the micromilling system and thin wall fabrication experiments have been conducted. It shows that the comprehensive dimensional error model and iterative compensation method are effective, and the dimension and shape precision of the micro straight thin wall has been obviously improved after the compensation of the radial cutting depth. The average relative errors have been reduced from 6.86% to 1.10%∼1.70%. The in-process compensation method introduced in this study is efficient and convenient as long as compensation strategies are integrated in the controlling unit for a specific micromilling process.

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Ultrasonic Vibration-Assisted Grinding of Carbon-Based Difficult-to-Cut Materials

Yan J.

Seimitsu Kogaku Kaishi/Journal of the Japan Society for Precision Engineering (Seimitsu Kogaku Kaishi/Journal of the Japan Society for Precision Engineering) 88 ( 7 ) 541 - 545 2022

ISSN 09120289

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A comparative study on mechanical polishing and laser polishing of laser-nitrided Zr-based metallic glass surface

Hong J., Zhang L., Zhang Z., Huang H., Yan J.

International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 124 ( 3-4 ) 959 - 971 2022

ISSN 02683768

As a promising surface modification method, nanosecond pulsed laser nitriding has been widely employed in enhancing the surface hardness and chemical corrosion of Zr-based metallic glass (MG). However, laser nitriding generally leads to poor finished surface quality, limiting its potential applications. For flattening the laser-nitrided surface, the most common methods, i.e., mechanical polishing (MP) and a novel proposed flattening approach, laser polishing (LP), were comparatively studied. A systematical comparison between MP and LP on three types of laser-nitrided surfaces was performed to evaluate the surface roughness, surface hardness, and plastic deformation. The experimental results indicate that the surface roughness of these three laser-nitrided surfaces is reduced by 56.4%, 58.1%, and 44.6% by MP. In contrast, a remarkable improvement in the surface quality is achieved with a maximum reduction in surface roughness by 80.4%, 81.5%, and 74.2% by LP, respectively. While in terms of the surface mechanical properties, the LP surfaces exhibit slightly lower hardness than the corresponding MP surfaces, which are both enhanced in hardness compared with as-cast MG. Additionally, no matter on the MP or LP surfaces, the shear bands and serrated flows have been significantly suppressed compared with as-cast MG, demonstrating that the micro-scale plastic deformation of as-cast MG has been modified. Although the obtained results indicate that the surface roughness of the laser-nitrided surface could be improved by both MP and LP, in terms of environmental friendliness, flexibility, and controllability, the LP shows dominant advantages and enormous potential in industry and consumer products.

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Effect of TiAlSiN coating residual stress on its sliding wear and cutting wear performance

Wu Z., Zheng G., Yan J., Cheng X., Liu H., Yang X.

International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 123 ( 11-12 ) 3885 - 3900 2022

ISSN 02683768

It is indispensable to explore the appropriate level of surface residual stress to enhance the wear resistance of coated tools. TiAlSiN-coated carbide tools with dissimilar surface residual compressive stresses (− 300 ~ − 600 MPa) are acquired via micro-sandblasting, which are used in the high-speed sliding friction experiments and turning experiments. The influence of residual stress on the sliding wear and cutting wear performance of TiAlSiN coated tools is investigated. The results show that with the improvement of surface residual compressive stress (absolute value), the friction coefficient and wear rate are reduced. The sliding wear resistance of the coated tool is enhanced. In addition, the cutting performance of the tool is also improved with the increase of residual compressive stress (absolute value). However, the excessive surface residual compressive stresses (absolute value) can lead to severe coating peeling, which in turn impairs the capability of wear resistance. The TiAlSiN-coated carbide tool with the stress of − 500 MPa presents the best wear resistance in the high-speed sliding wear and cutting wear process.

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New insights into the mechanisms of ultrasonic vibration cutting of brittle materials via multi-cyclic nanoindentation

Huang W., Yan J.

European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 22nd International Conference and Exhibition, EUSPEN 2022 (European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 22nd International Conference and Exhibition, EUSPEN 2022) 501 - 504 2022

Ultrasonic vibration cutting is a potential method for ductile machining of brittle materials. Although there are some research works trying to answer why the ultrasonic vibration promotes ductile machining of brittle materials, most of them are based on geometrical and kinematic analysis. In this study, plunge-cutting experiments under the conventional and vibration-assisted cutting conditions were conducted on single crystalline silicon and the results were compared to those of multi-cyclic nanoindentation tests. The surface morphology and subsurface microstructure of both machined grooves and residual indents were characterized. Results of plunge-cutting experiments show that with ultrasonic vibration cutting, the critical depth of cut for ductile-to-brittle transition and the amorphous phase in cutting chips are increased compared with conventional cutting. Results of multi-cyclic nanoindentation tests show that the indentation-induced amorphous layer increased as the cyclic number increased, which is consistent with the cutting results. The findings from this study may help understand the removal mechanism of brittle materials during ultrasonic vibration cutting.

Optimization of fast tool servo diamond turning for enhancing geometrical accuracy and surface quality of freeform optics

Zhang L., Sato Y., Yan J.

Fast tool servo (FTS) diamond turning is a promising technique for high-precision generation of freeform optics with remarkable efficiency. However, the conventional constant scheme for control point sampling fails to consider the surface variation, which might lose some details of the surface profile and result in low form accuracy and non-uniform surface quality. Facing this issue, this manuscript proposes a novel optimization method for control points sampling, which restrains the deviations and contains as much of the surface details. In the optimization method, the sampling intervals between two adjacent control points are actively adjusted to adapt the surface variation of the desired surface. By adopting this method, the sampling induced interpolation error between the control points is restrained within the tolerance and eliminates lack/over-definition of control points in the machining area. The feasibility of the proposed optimization method is demonstrated by both theoretical prediction and fabrication experiment of sinusoid freeform surface. Compared with the conventional sampling method, both the predicted and measured form error of the proposed method are remarkably reduced about 35 % with the same amount of control points. This technique provides a new route to sampling control points in FTS diamond turning to achieve high accuracy and flexible fabrication of freeform surface machining.

Surface functionalization of Zr-based metallic glass by direct nanosecond laser texturing

Y Qian, M Jiang, Z Zhang, H Huang, J Yan

Vacuum 194, 110635 (Elsevier {BV}) 194 110635 2021.12

ISSN 0042207X

The functional properties of metallic glasses (MGs) can be enhanced by introducing special micro/nano-structures on their surface. In this study, a nanosecond pulsed laser was used to texture micro-convex array structures with different pitches (P) on a Zr-based MG surface to enrich its engineering applications. The reflection characteristics and wettability of polished and textured surfaces were compared. The experimental results showed that unlike the bright spot reflected from the polished surface, the light reflected from the textured surface would induce a well-defined diffraction pattern. In addition, the wettability of the surfaces covered with micro-convex array structures was also different from that of the polished surface. That is, without post-processing, the textured array structures would promote hydrophilicity; while after exposing in the air for 100 days or fluoroalkylsilane modification, the textured array structures facilitated hydrophobicity.

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Evolution and control of deformation mechanisms in micro-grooving of Zr-based metallic glass

P Qiu, B Meng, S Xu, Y Rong, J Yan

Journal of Manufacturing Processes 68, 923-931 (Journal of Manufacturing Processes) 68 923 - 931 2021.08

ISSN 15266125

The evolution of deformation mechanisms with increasing depth of cut (DOC) in micro-grooving of Zr-based metallic glass was deeply investigated in this study for the first time. The micro-grooving characteristics of metallic glass were initially studied by nanoscratch test, which verified that the material removal mode abruptly changes from extrusion mode to cutting mode with increase of DOC. Based on the free-volume theory, a dynamic model coupling stress, temperature and free volume concentration was used to simulate the change of deformation characteristics with DOC. The results showed that the deformation mechanism of metallic glass is closely related to free volume flow, which is significantly affected by average strain rate and free volume flow coefficient in deformation zone and can be tuned with different DOC. Considering that free volume flow is determined by its flow coefficient and concentration, we proposed to control the deformation characteristics of metallic glass in micro-grooving by heat treatment and verified its effectiveness experimentally.

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On the transformation between micro-concave and micro-convex in nanosecond laser ablation of a Zr-based metallic glass

Y Qian, M Jiang, Z Zhang, H Huang, J Yan

Journal of Manufacturing Processes 68, 1114-1122 (Journal of Manufacturing Processes) 68 1114 - 1122 2021.08

ISSN 15266125

Understanding the physical mechanism of laser-material interaction is significant and meaningful in both pure science and engineering applications. Laser ablation induced micro-concave is a commonly-observed phenomenon, but the formation of micro-convex by laser ablation is rarely reported. In this study, the transformation in surface microstructure from micro-concave to micro-convex, then to micro-concave again was reported for the first time in laser ablation of a typical Zr-based metallic glass (MG). The experimental results indicated that such transformations strongly depended on the peak laser power intensity and number of laser pulses. The coupling effects of the recoil pressure and Marangoni flow were proposed to explain the observed transformation. By locally overlapping adjacent micro-convexes, various surface patterns could be fabricated on the MG surface, which could tune its surface wettability. This study would not only enhance the understanding of laser-MG interaction but also provide new methods for patterning MG surface.

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Evolution of high-pressure metastable phase Si-XIII during silicon nanoindentation: A molecular dynamics study

Zhang L., Yan J.

Computational Materials Science (Computational Materials Science) 191 2021.04

ISSN 09270256

© 2021 Elsevier B.V. Berkovich indenters are widely employed in nanoindentation experiments of single-crystal silicon, in molecular dynamic simulations of silicon nanoindentation, however, spherical indenters are generally employed. To close this gap, in this paper, a series of molecular dynamic simulations are conducted on (0 0 1), (1 0 1), and (1 1 1) silicon surfaces to explore the evolution of high-pressure phases. Several possible silicon phases are tracked by coordination number (CN), radial distribution function (RDF), and angular distribution function (ADF). Results show that the metastable phases and the high-pressure phases present different symmetrical patterns along different crystallographic orientations. A large amount of high-pressure phase Si-XIII, which is seldomly observed in nanoindentation using a spherical indenter, is first discovered under the Berkovich indenter, and the evolution mechanism is characterized by tracking the position transition of labeled silicon atoms. As a transition phase for high-pressure phase Si-II and Si-XIII, bct5 phase is found in the {1 1 1} [1 1 0] slip systems, which is related with slipping flatten lattice structures. Different from the phase transformation criterion for Si-II, the transformation from Si-I to Si-XIII companies with the local elastic deformation of (0 0 1) surface. The atoms in the three neighboring unit cells are compressed into a uniform long-distance ordered crystal structure. Upon indenter extraction and rapid stress releasing, the elastic deformation of the crystal surface resumes incompletely. A part of Si-XIII recovers to pristine Si-I and the rest changes into amorphous phase. The distribution of local hydrostatic pressure and von Mises stress in the phase transformation regions indicates that the concentrated hydrostatic pressure and specific stress induce this high-pressure silicon phase. This research clarifies the evolutionary process of Si-XIII phase generation and enriches fundamental understanding on the mechanisms of silicon phase transformations in nanoindentation.

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Annealed high-phosphorus electroless Ni–P coatings for producing molds for precision glass molding

Yu Q., Zhou T., He Y., Liu P., Wang X., Jiang Y., Yan J.

Materials Chemistry and Physics (Materials Chemistry and Physics) 262 2021.04

ISSN 02540584

© 2021 Elsevier B.V. An annealed high-phosphorus electroless Ni–P coating was developed as the mold material for precision glass molding. The coating with a phosphorus content of 11.6 wt% was prepared on heat-resistant stainless steel via an intermittent ultrasonic-assisted electroless plating method. The effects of annealing temperature and heating rate on phase transformation, grain size variation, and mechanical properties were investigated. An annealing temperature of 600 °C with a heating rate of 5 °C/min was determined to be the optimal choice for heat treatment. Microgrooves were machined on the coating surface. After heat treatment, the increased hardness and modulus helped the microgrooves on the coating resist thermal deformation during the PGM process. The PV value decreased from 0.58 to 0.32 μm, and the surface roughness decreased from Sa 104.5 to Sa 62.6 nm. The mold produced by heat-treated coating was beneficial for improving the forming accuracy of precision glass molding.

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Deterministic error compensation for slow tool servo-driven diamond turning of freeform surface with nanometric form accuracy

Nagayama K., Yan J.

Journal of Manufacturing Processes (Journal of Manufacturing Processes) 64 45 - 57 2021.04

ISSN 15266125

© 2021 The Society of Manufacturing Engineers Slow tool servo (STS) turning takes an important role in fabrication of freeform optical elements. However, in conventional STS turning, it is technologically difficult to obtain nanometer-level form accuracy due to multiple error factors such as tool trajectory errors, tool alignment errors and dynamic follow-up errors of machine tools used. In this study, a deterministic process flow was proposed where all the main error factors were comprehensively analyzed, simulated and then compensated before machining based on the feedforward method, and the workpiece form error after compensation was predicted accurately. The proposed process flow enabled achieving nanometer-level form accuracy by a single cut without the necessity of repetitive trial-and-error. To demonstrate the effectiveness of the proposed method, cutting tests of a two-dimensional sine wave grid were attempted on single-crystal silicon and the proposed error compensation was applied. As a result, the form error was reduced to 8 nm P–V (peak to valley) with a surface roughness of 1 nm Sa by a single cut.

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Diffraction manipulation of visible light with submicron structures for structural coloration fabrication

He Y., Zhou T., Dong X., Zhu Z., Yu Q., Liu P., Zhao W., Wang X., Hu Y., Yan J.

Optics Express (Optics Express) 29 ( 6 ) 9294 - 9311 2021.03

© 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement The structural coloration of glass induced by submicron structures is eco-friendly, ink-free, and has profound scientific significance. However, it is difficult to manufacture the submicron structures for glass optics due to the high hardness of glass and the miniature size of the microstructures. In this paper, the diffraction manipulation mechanism of groove shape to structural coloration and optimization theory are studied by establishing the theoretical and simulation mode. Moreover, a newly-developed axial-feed fly-cutting (AFC) technology and the PGM technology are introduced to precisely create the designed submicron V-shape grooves and structural color pattern on a Ni-P mold and then replicating them on a glass surface. Between these two kinds of typical submicron grooves that can be machined by mechanical cutting technology, it is found that the diffraction intensity and efficiency of V-shape grooves are higher than these of jagged-shape grooves, which indicates that V-shape grooves is more suitable to be used for structural coloration with high brightness. The structural color resolution is dramatically increased with the reduction of groove spacing and can be flexibly regulated by AFC, which significantly contributes to the structural coloration manufacturing. Structural pixel segments composed of submicron grooves are arranged row-by-row to form color patterns, and the letters of different colors are fabricated on the mold and transferred to the glass surface. Methods of optical diffraction manipulation, flexible manufacturing of submicron structures, and structural color image construction proposed in this paper for the production of a structural color pattern are beneficial to a wide range of fields.

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Chip-free surface patterning of toxic brittle polycrystalline materials through micro/nanoscale burnishing

Huang W., Yan J.

International Journal of Machine Tools and Manufacture (International Journal of Machine Tools and Manufacture) 162 2021.03

ISSN 08906955

© 2021 Elsevier Ltd Brittle crystalline materials have important applications in optics and optoelectronics. However, their powders are highly toxic; thus, the chips generated in material removal processes such as cutting, grinding, and polishing are harmful to human health and the environment. In this study, micro/nanoscale burnishing tests were conducted on polycrystalline zinc selenide (p-ZnSe) to explore the feasibility of high-precision surface patterning of a toxic material by local plastic deformation without chip generation. The local deformation behaviours and subsurface damage formation mechanisms were investigated under dry and oil-lubricated conditions. Two types of cracks occurred when the force exceeded a critical value: cracks along the slip planes at the groove bottom and cracks along the cleavage planes at the groove edge. Below the critical force value, however, a crack-free surface was obtained with lower surface roughness than those for diamond-turned surfaces. No phase transformation was detected after burnishing, but lattice distortion appeared in the subsurface layer. A model was developed to predict the activated slip planes by calculating the maximum Schmid factors of the slip systems, and the distribution of subsurface defects was clarified by cross-sectional direct observations. It was also found that the use of a lubricating oil could greatly reduce material pile-ups around the tool. As test pieces, microgrid patterns were fabricated by crossing and overlapping the grooves, and smooth surfaces with surface roughness of 1.85 nm Sa and 4.5 nm Sa, respectively, were achieved. The findings from this study demonstrate the feasibility of chip-free surface patterning on toxic brittle polycrystalline materials by micro/nanoscale burnishing, which is an effective alternative to cutting and grinding for the fabrication of micro structured optical elements and microfluidics.

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Fundamental Investigation of Diamond Cutting of Micro V-shaped Grooves on a Polycrystalline Soft-Brittle Material

W Huang, J Yan

Journal of Manufacturing and Materials Processing 5 (1), 17 (Journal of Manufacturing and Materials Processing) 5 ( 1 ) 2021.03

Fabricating micro-structures on optical materials has received great interest in recent years. In this work, micro-grooving experiments were performed on polycrystalline zinc selenide (ZnSe) to investigate the feasibility of surface micro-structuring on polycrystalline soft-brittle material by diamond turning. A photosensitive resin was coated on the workpiece before cutting, and it was found that the coating was effective in suppressing brittle fractures at the edges of the grooves. The effect of tool feed rate in groove depth direction was examined. Results showed that the defect morphology on the groove surface was affected by the tool feed rate. The crystallographic orientation of grains around the groove was characterized by electron backscatter diffraction (EBSD), and it was found that the formation of defects was strongly dependent on the angle of groove surface with respect to the cleavage plane of grain. The stress distribution of the micro-grooving process was investigated by the finite element method. Results showed that the location of tensile stresses in the coated workpiece was farther from the edge of the groove compared with that in the uncoated workpiece, verifying the experimental result that brittle fractures were suppressed by the resin coating.

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One-step fabrication of regular hierarchical micro/nano-structures on glassy carbon by nanosecond pulsed laser irradiation

Wang C., Huang H., Qian Y., Zhang Z., Yan J.

Journal of Manufacturing Processes (Journal of Manufacturing Processes) 62 108 - 118 2021.02

ISSN 15266125

Fabrication of hierarchical micro/nano-structures on glassy carbon (GC) surface is important for the application of GC as the mold material for glass molding, but it is still challenging due to the high brittleness and hardness of the material. In this study, by using a nanosecond pulsed laser, a hierarchical micro/nano-structure, i.e., micro-dimple with ring-like nanostructure on its inner wall, was generated on the GC surface. The effects of laser parameters, such as laser irradiation time and fluence, on the formation and evolution of the hierarchical micro/nano-structure were experimentally studied. By comparative experiments with graphite, the role of amorphous nature of GC on the formation of very regular hierarchical micro/nano-structure was confirmed. The results obtained by irradiating GC in argon and nitrogen gas further indicated that the formation of hierarchical micro/nano-structure was independent of the gas atmosphere. By controlling the relative positions of point shots, various micro-dimple arrays were successfully fabricated on the GC surface which significantly changed its wetting behavior. Finally, formation mechanism of the hierarchical micro/nano-structure was discussed according to the experimental results as well as some previous literatures. This study provides a one-step method for fabricating hierarchical micro/nano-structures on the GC surface by nanosecond pulsed laser irradiation, which would be meaningful for the functional applications of GC.

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Nanosecond pulsed laser-induced formation of nanopattern on Fe-based metallic glass surface

Y Qian, H Huang, M Jiang, J Yan

Applied Surface Science, 151976 (Applied Surface Science) 577 2021

ISSN 01694332

Fe-based metallic glasses (MGs) have attracted much attention because of their cheap raw materials, outstanding soft magnetic properties and superior catalytic activity. Meanwhile, the fabrication of micro/nano-structures on its surface could further improve its functional properties. In this study, it was attempted to fabricate micro/nano-structures on a Fe-based MG (Fe52Cr13Mo12C15B6Er2, in at. %) surface by nanosecond pulsed laser irradiation technology. The surface characteristics and microstructural evolution of Fe-based MG were investigated. The experimental results showed that under different laser fluences, the laser-irradiated areas exhibited distinguished microstructures, i.e., nanoparticles, the network nanostructures or a combination of these two microstructures. Furthermore, oxygen and erbium were enriched inside the network nanostructures. By analyzing the microstructural evolution, formation mechanisms of the nanoparticles and the network nanostructures were discussed. The nanoparticles were actually caused by laser-induced element enrichment (i.e. amorphous erbium oxide) and the mismatch of its wettability with the substrate; the formation of the network nanostructures was attributed to the diffusion and connection of nanoparticles under the combined influence of recoil pressure and surface topography.

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Machinability exploration for high-entropy alloy FeCrCoMnNi by ultrasonic vibration-assisted diamond turning

L Zhang, T Hashimoto, J Yan

CIRP Annals (CIRP Annals) 70 ( 1 ) 37 - 40 2021

ISSN 00078506

High-entropy alloy (HEA) is an emerging alloy which consists of five or more metallic elements with equimolar concentrations and exhibits excellent mechanical properties at cryogenic temperature. However, its machinability is almost unknown. In this study, high frequency one-dimensional ultrasonic vibration-assisted diamond turning (UVDT) experiments were conducted on an FeCrCoMnNi-based HEA to investigate the micro-nanoscale material removal mechanisms. Compared with conventional diamond turning, UVDT produced thinner chips, lower cutting forces, less tool wear and better surface integrity. Due to the ultrasonic vibration-assisted burnishing effect, surface scratches were significantly eliminated. A freeform surface was test-fabricated with optical-level finish.

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Effects of relative tool sharpness on surface generation mechanism of precision turning of electroless nickel-phosphorus coating

Q Yu, T Zhou, Y He, P Liu, X Wang, J Yan

Journal of Mechanical Science and Technology, 1-9 (Journal of Mechanical Science and Technology) 35 ( 7 ) 3113 - 3121 2021

ISSN 1738494X

Relative tool sharpness (RTS) is identified as the ratio of undeformed chip thickness to tool cutting edge radius. This paper studies the effects of RTS on the surface generation mechanism of precision turning of electroless nickel-phosphorus (Ni-P) coating. An R-shaped tungsten carbide (WC) tool was adopted for the face turning experiment. The cutting edge radius was 1.84 µm measured by a laser scanning confocal microscope (LSCM). The chip formation behavior, cutting forces and surface morphology were investigated under different RTS values. Results showed that the chip changes from continuous to discontinuous as RTS decreases from 0.54 to 0.27, indicating the transition of the material removal mechanism. The periodical fluctuations with small amplitudes on the machined surface are associated with the high-frequency tool-tip vibration. The low-frequency fluctuations of the cutting forces are related to the material swelling and recovery. The optimal machined surface roughness was obtained at the RTS of 0.38.

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Laser nitriding of Zr-based metallic glass: An investigation by orthogonal experiments

J Hong, Y Qian, L Zhang, H Huang, M Jiang, J Yan

Surface and Coatings Technology, 127657 (Surface and Coatings Technology) 424 2021

ISSN 02578972

Laser nitriding is a useful method to improve the surface hardness of materials, and it has been newly introduced to harden the surface of Zr-based metallic glass (MG). However, the currently achieved improvement in surface hardness is only 15.7%. To explore the potential of laser nitriding of Zr-based MG, orthogonal experiments were designed and performed in this study. By nanosecond pulsed laser irradiation in nitrogen atmosphere, the effects of laser parameters (average laser power, scanning speed, overlap rate and number of irradiation cycle) on the surface hardness of Zr-based MG were systematically investigated. The experimental results showed the highest surface hardness reached 18.21 GPa (Meyer's hardness) by orthogonal design, which is about 2 times higher than that of the as-cast MG. Furthermore, the laser affecting layer consisting of nitride phase reached tens of microns. The obtained results demonstrated that significant improvement in surface hardness could be achieved by selecting appropriate laser irradiation parameters, which would be beneficial to the engineering applications of MGs as surface contact materials.

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Machinability Investigation for Cellulose Nanofiber-Reinforced Polymer Composite by Ultraprecision Diamond Turning

Y Kamada, J Yan

International Journal of Automation Technology 15 (4), 475-482 (富士技術出版株式会社) 15 ( 4 ) 475 - 482 2021

ISSN 1881-7629

Cellulose nanofiber (CeNF)-reinforced polymer composites have wide potential applications in the manufacturing of optical and mechanical parts owing to their light weight, high mechanical strength, and optical transparency. In this study, CeNF-reinforced homogeneous polypropylene (PP-CeNF) was machined under various conditions by ultraprecision diamond turning, and the results were compared with those of pure PP without CeNF addition. The influence of CeNFs on material removal was investigated by examining the surface topography, chip morphology, cutting forces, and cutting temperature. It was found that the surface defects in pure PP cutting were surface tearing, while the surface defects of PP-CeNF were surface tearing and micro-holes induced by the pulling-outs of CeNFs. Surface tearing increased with cutting speed; pulling-outs of CeNFs were slightly affected by cutting speed but strongly dependent on the tool feed rate. Under a small tool feed rate, the surface roughness could be reduced to ∼10 nm Ra for PP-CeNF. The thermal effect was insignificant in the experiments, whereas the effect of strain rate-induced material hardening was dominant for both workpiece materials at a high cutting speed. This study helps to understand the mechanisms for ultraprecision cutting of CeNF-reinforced polymer composites and provides guidelines for improving the machined surface quality.

Tribological characteristics of electrical discharge coated layers using quarry dust suspension

CY Yap, PJ Liew, ISB Othman, MFB Abdollah, J Yan

Surface and Coatings Technology, 127895 (Surface and Coatings Technology) 428 2021

ISSN 02578972

In this research, a coating layer was formed on the tungsten carbide cobalt (WC-Co) substrate surface by using electrical discharge coating (EDC) with waste quarry dust powder suspension. The tribological test was carried out by using a micro pin-on-disc tribometer at a constant normal load (10N) and sliding speed (5 mm/s). The surface roughness, Vickers micro-hardness, coefficient of friction (CoF), wear weight loss, wear scar depth and wear track morphology of the coating layer were investigated and compared with the original surface of the WC-Co substrate in this study. The results indicated that under coating conditions of 5 A of peak current (Ip) and 300 μs of pulse on time (Ton), the Vickers micro-hardness increased by 28%, and the surface roughness, CoF, wear weight loss, and wear scar depth of coating layer reduced by 29%, 61%, 79%, 63%, respectively compared with the original WC-Co substrate. These results demonstrated that the coating layers produced by EDC with quarry dust waste powder suspension had good wear resistance, which could be beneficial to the cutting tool, mold and die industries.

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Laser induced micro-cracking of Zr-based metallic glass using 1011 W/m2 nano-pulses

Huang H., Qian Y., Wang C., Yan J.

Materials Today Communications (Materials Today Communications) 25 2020.12

© 2020 Elsevier Ltd Low power nanosecond laser irradiation has potential applications in surface processing of metallic glasses (MGs). However, the response of MGs to a relatively low power intensity (1011 W/m2) has not been investigated. In this study, surface microstructures and characteristics of Zr-based MG after low power nanosecond laser irradiation were studied. Micro-cracks with depth in nanoscale and width in microscale were observed on the irradiated MG surface. The effects of laser parameters on the formation and evolution of micro-cracks were further investigated, and surface characteristics were characterized by using X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). The results showed that under the peak laser power intensity of 2.3 × 1011 W/m2, when increasing the scanning speed from 1 to 5 mm/s, the maximum width of micro-cracks reduced from 3 μm to be less than 1 μm; further increasing to 10 mm/s, no micro-cracks appeared. When increasing the laser power intensity, the micro-groove structure would be formed with pileup around it and line cracks, open cracks and laser pulse tracks on it. During multi-line laser scanning, the pulse overlap rate also affected the formation and distribution of micro-cracks. At last, the formation mechanism of micro-cracks was discussed. These results would be meaningful for understanding the laser-MG interaction as well as guiding the selection of laser parameters for various applications.

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Algorithm of Micro-Grooving and Imaging Processing for the Generation of High-Resolution Structural Color Images

Zhou T., He Y., Wang T., Dong X., Liu P., Zhao W., Hu Y., Yan J.

Nanomanufacturing and Metrology (Nanomanufacturing and Metrology) 3 ( 3 ) 187 - 198 2020.09

ISSN 2520811X

© 2020, International Society for Nanomanufacturing and Tianjin University and Springer Nature Singapore Pte Ltd. The use of submicron structures for structural coloration of surfaces has broad applications for color filters, projection displays, virtual reality, and anti-counterfeiting. Currently, structural color images lack high resolution due to low manufacturing accuracy. In this study, the axial-feed fly cutting (AFC) method is proposed to fabricate submicron grooves for the diffraction of visible light to create structural color images. We establish the relationship between the color information in the pixels of the original image and the parameters of the array units corresponding to the pixels. An algorithm to determine groove spacing and the tool path is established, and array units with the desired groove spacing are machined to reproduce the structural color images. The submicron grooves fabricated by AFC have high quality and good consistency. Due to the excellent diffraction performance of the machined grooves, images with high saturation and resolution can be reproduced. It is verified that images with various colors can be efficiently fabricated using the proposed method and algorithm.

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Generation of high-saturation two-level iridescent structures by vibration-assisted fly cutting

He Y., Zhou T., Dong X., Liu P., Zhao W., Wang X., Hu Y., Yan J.

Materials and Design (Materials and Design) 193 2020.08

ISSN 02641275

© 2020 The Authors The submicron-level structured surface induces viewing-angle-dependent iridescence, and has wide applications in multi-color printing, micro-display projection, invisibility cloak technology. In this study, several types of two-level structures, which consist of the first-order micro geometric features corresponding to the pattern shape and the second-order submicron grooves corresponding to the diffraction grating, are designed to directly induce a variety of iridescent patterns based on their shape regulations. To fabricate these two-level iridescent structures with high accuracy in a single step, vibration-assisted fly cutting (VAFC) is proposed. VAFC involves the low-frequency vibration of the workpiece in the vertical direction during the feed in the horizontal direction and the high-speed rotation of the diamond cutting tool. A 3D theoretical model is established for the numerical simulation of the generating process of the iridescent structures and the regulation of the first-order geometric feature by vibration parameters. As the key parameter to the iridescent color, the spacing of the second-order submicron grooves is flexibly controlled by the feed rate. A VAFC platform is developed to fabricate the two-level structures and an optical detection system is setup to test the surface iridescence. Various vivid colors are regulated by the two-level structures with high saturation and uniformity.

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Silicon nanoparticle generation and deposition on glass from waste silicon powder by nanosecond pulsed laser irradiation

Momoki K., Manabe T., Li L., Yan J.

Materials Science in Semiconductor Processing (Materials Science in Semiconductor Processing) 111 2020.06

ISSN 13698001

© 2020 Elsevier Ltd Silicon nanoparticles can be used for fabricating electrodes in high-performance lithium ion batteries and other high value-added products. Currently, silicon nanoparticles are fabricated by pulsed laser irradiation of single-crystal silicon wafers in water. In this study, we proposed silicon nanoparticle generation by using a nanosecond pulsed laser to irradiate waste silicon powder which is disposed from wire-saw slicing processes of silicon ingots. The laser-induced nanoparticles were backward-transferred and deposited on a glass substrate. It was found that the morphology and amount of the deposited nanoparticles was strongly dependent on the distance between the glass substrate and the waste silicon powder target. Raman spectroscopy showed that the silicon nanoparticles were crystalline, and the average size was ~10 nm. The obtained silicon nanoparticles had high purity, as the diamond abrasives included in the waste silicon powder were removed through oxidation and vaporization during laser irradiation.

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Generating Nanodot Structures on Stainless-Steel Surfaces by Cross Scanning of a Picosecond Pulsed Laser

Kobayashi T., Yan J.

Nanomanufacturing and Metrology (Nanomanufacturing and Metrology) 3 ( 2 ) 105 - 111 2020.06

ISSN 2520811X

© 2020, The Author(s). Ultrashort pulsed laser-induced periodic surface structures (LIPSS) can be generated on different kinds of materials, which are widely utilized for modifying surface properties such as wettability, adhesion, and tribological, as well as optical performances. Previous studies have focused mainly on one-dimensional LIPSS (i.e., line structure) generation. In this study, a picosecond pulsed laser was used to irradiate stainless-steel surfaces for generating two-dimensional LIPSS, namely nanodot structures, by cross-scanning the laser beam for a different number of times. The obtained nanodot structures were found to be super hydrophilic just after laser irradiation, but turned to be hydrophobic after exposure in air for a few days. By cross-scanning the laser beam for the same number of times, local LIPSS rewriting was realized. This study showed the possibility of improving the homogeneity of the surface properties of steel materials through laser-induced nanodot structuring.

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Surface formation mechanism in ultraprecision diamond turning of coarse-grained polycrystalline ZnSe

Huang W., Yan J.

International Journal of Machine Tools and Manufacture (International Journal of Machine Tools and Manufacture) 153 2020.06

ISSN 08906955

© 2020 Elsevier Ltd Zinc selenide is an excellent infrared optical material. In this study, ultraprecision diamond turning experiments were carried out on coarse-grained polycrystalline ZnSe (p-ZnSe) under various conditions and the corresponding surface formation mechanisms were investigated by examining the surface topography, chip morphology, material microstructural change, and cutting forces. Two kinds of surface defects were observed (i.e. plowing-induced micron-scale cleavage craters and tearing-induced submicron-scale tearing pits). It was determined that plowing induced micron-scale cleavage craters could be suppressed by reducing undeformed chip thickness. Furthermore, it was ascertained that tearing-induced submicron-scale tearing pits could be restrained by using a cutting tool with a zero rake angle. The minimal surface roughness was dominated by grain boundary steps formed when the cutting tool crossed twin boundaries at a large angle. A model was proposed for correlating surface defects and boundary steps with crystal orientations and cutting directions. By using a large-nose diamond tool for cutting, a smooth surface of 1.5 nm Sa was obtained. In addition, a zinc blende to cinnabar phase transformation was observed in the cutting chips, and metallization of cutting chips occurred at an extremely small undeformed chip thickness (~20 nm). Moreover, it was discovered that phase transformation inside the workpiece depends on the radius of the tool nose. The findings of this study provide an important reference for ultraprecision machining of brittle polycrystalline materials.

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Drilling of cemented carbide by ultrasonic vibration-assisted grinding on a flexible stage

A. Teramachi, S. Tarvainen, J. Yan

Journal of the Japan Society for Abrasive Technology 64 ( 6 ) 320 - 325 2020.06

Research paper (scientific journal), Joint Work, Accepted

Additive manufacturing of three-dimensional metal-glass functionally gradient material components by laser powder bed fusion with in situ powder mixing

Zhang X., Chueh Y.h., Wei C., Sun Z., Yan J., Li L.

Additive Manufacturing (Additive Manufacturing) 33 2020.05

© 2020 Elsevier B.V. Existing commercial three-dimensional (3D) printing systems based on powder bed fusion approach can normally only print a single material in each component. In this paper, functionally gradient materials (FGM) with composition variation from a copper alloy to a soda-lime glass were manufactured using a proprietary nozzle-based multi-material selective laser melting (MMSLM) system. An in situ powder mixing system was designed to mix both metal and glass powders at selective ratios and the mixed powders were dispensed with an ultrasonic vibration powder feeding system with multiple nozzles. From the cross section analysis of the gradient structures, glass proportion increased gradually from the metallic matrix composite (MMC), transition phase to ceramic matrix composite (CMC). The pure copper alloy joined the MMC part and the pure glass phase penetrated into the CMC part during laser processing, which anchored the glass phase, as the main mechanism of combining pure metal and pure glass by FGM in 3D printed parts. From results of indentation, tensile and shear tests on the gradient material samples, it showed that mechanical properties of the FGM gradually changed from ductility (metal side) to brittle (glass side). The weakest part of the FGM structure occurred at the interface between transition phase and the CMC, which was also the interface between the ductile and brittle phases.

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Generating silicon nanofiber clusters from grinding sludge by millisecond pulsed laser irradiation

Momoki K., Takahashi K., Kobinata K., Kobayashi Y., Kawai A., Yan J.

Nanomaterials (Nanomaterials) 10 ( 4 ) 2020.04

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Silicon nanofiber clusters were successfully generated by the irradiation of millisecond pulsed laser light on silicon sludge disposed from wafer back-grinding processes. It was found that the size, intensity, and growing speed of the laser-induced plume varied with the gas pressure, while the size and morphology of the nanofibers were dependent on the laser pulse duration. The generated nanofibers were mainly amorphous with crystalline nanoparticles on their tips. The crystallinity and oxidation degree of the nanofibers depended on the preheating conditions of the silicon sludge. This study demonstrated the possibility of changing silicon waste into functional nanomaterials, which are possibly useful for fabricating high-performance lithium-ion battery electrodes.

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Effect of relative tool sharpness on subsurface damage and material recovery in nanometric cutting of mono-crystalline silicon: A molecular dynamics approach

Ameli Kalkhoran S., Vahdati M., Yan J.

Materials Science in Semiconductor Processing (Materials Science in Semiconductor Processing) 108 2020.03

ISSN 13698001

© 2019 Elsevier Ltd Depth of cut (h0) and tool edge radius (re) are two key parameters in nanometric cutting, investigating both of the two parameters simultaneously can provide comprehensive understanding of the cutting mechanism. In this paper, relative tool sharpness (RTS), which is quantified as h0/re, is employed as a factor to examine the subsurface damage and material recovery in nanometric cutting of mono-crystalline silicon using molecular dynamics (MD) simulation. Various RTS values were generated by changes of cutting depth at different tool edge radius of 1, 3 and 5 nm respectively. Results indicate that there is always a layer of particles which sticks on the tool surface and influences the machined surface, even at RTS = 0. Besides that, the increase of RTS results in subsurface damage layer serration, which is caused by stick-slip phenomenon between the tool and workpiece. A bigger RTS causes a bigger depth of serrations, although the number of serrations remains constant. Increase in RTS also causes the formation of the hexagonal diamond structure. The material recovery drops dramatically by RTS increase. Using a sharper tool edge (RTS<0.25) at a cutting depths below 1 nm does not necessarily decrease subsurface damage due to the drastic stress concentration. It is also demonstrated that silicon amorphisation can occur in the unmachined region in front of the tool due to the hydrostatic pressure wave caused by tool advancement.

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Electrical Discharge/Electrochemical Hybrid Machining Based on the Same Machine and Tool Electrode

R Kishi, J Yan

Journal of Micro and Nano-Manufacturing 8 (1) (Journal of Micro and Nano-Manufacturing) 8 ( 1 ) 2020.03

ISSN 21660468

Electrical discharge machining (EDM) causes surface defects such as resolidified layer and microcracks, and a finishing process is usually needed to remove these defects. In this paper, a hybrid process was proposed where electrochemical machining (ECM) was performed as a finishing process after EDM using the same tool electrode on the same machine. By using two kinds of disk-type rotary electrodes, rectangular grooves and grooves with convex inner structures were fabricated. Surface topography were investigated by using scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDX), and laser-probe surface profilometer. The material removal mechanism of resolidified layers was clarified. The surface roughness of the rectangular groove was improved from 3.82 μm Ra to 0.86 μm Ra after ECM. Electrode rotation was effective for flushing electrolytic products when fabricating inner structures. As there is no need for exchanging tools and machines, tool alignment error can be prevented and productivity can be improved. Therefore, the proposed EDM/ECM hybrid process contributes to rapid fabrication of microscale products with high surface integrity.

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Effects of deep subsurface damages on surface nanostructure formation in laser recovery of grinded single-crystal silicon wafers

Niitsu K., Yan J.

Precision Engineering (Precision Engineering) 62 213 - 222 2020.03

ISSN 01416359

© 2019 Elsevier Inc. A nanosecond pulsed Nd:YVO4 laser was irradiated on a boron-doped single-crystal silicon wafer after rough and fine grinding processes to recover the grinding-induced subsurface damages. The surface topography of samples was investigated by using a white-light interferometer, a scanning electron microscope, and an atomic force microscope; while the crystallinity was analyzed by a laser micro-Raman spectrometer. It was found that surface nanostructures were generated by the Mullins-Sekerka instability, which remained on the surface under recoil pressure and surface tension. The rough grinding-induced deep subsurface damages influenced the interface instability between liquid and solid silicon during recrystallization process. By increasing pulse width and decreasing laser peak irradiance, the subsurface damage was recovered and a flat surface with surface roughness of ~1 nm Sa was obtained. This study reveals important correlations among grinding-induced latent subsurface defects, laser peak irradiance and nanoscale surface topography formation in laser recovery, which contributes to high quality silicon wafer manufacturing.

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Surface modification and functionalization by electrical discharge coating: A comprehensive review

Liew P.J., Yap C.Y., Wang J., Zhou T., Yan J.

International Journal of Extreme Manufacturing (International Journal of Extreme Manufacturing) 2 ( 1 ) 2020.03

ISSN 26318644

© 2020 The Author(s). Published by IOP Publishing Ltd on behalf of the IMMT Hard coatings are extensively required in industry for protecting mechanical/structural parts that withstand extremely high temperature, stress, chemical corrosion, and other hostile environments. Electrical discharge coating (EDC) is an emerging surface modification technology to produce such hard coatings by using electrical discharges to coat a layer of material on workpiece surface to modify and enhance the surface characteristics or create new surface functions. This paper presents a comprehensive overview of EDC technologies for various materials, and summarises the types and key parameters of EDC processes as well as the characteristics of resulting coatings. It provides a systematic summary of the fundamentals and key features of the EDC processes, as well as its applications and future trends.

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Nanoparticle generation from various types of silicon materials by nanosecond-pulsed laser irradiation

Momoki K., Yan J.

Applied Physics Express (Applied Physics Express) 13 ( 2 ) 2020.02

ISSN 18820778

© 2020 The Japan Society of Applied Physics. A huge amount of silicon sludge is disposed of from silicon wafer manufacture, and its reuse is a critical issue. In this study, silicon nanoparticle generation from sludge was explored by nanosecond-pulsed laser irradiation. The nanoparticle production efficiency from silicon sludge was compared with that from silicon wafers. The result showed that using silicon sludge as a laser irradiation target leads to a distinctly higher production efficiency of nanoparticles; the smaller the powder size of the silicon sludge, the higher the efficiency. The generated silicon nanoparticles were crystalline with sizes at the 10 nm level.

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Direct observation of discharging phenomena in vibration-assisted micro-electrical discharge machining

Shitara T., Fujita K., Yan J.

International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 108 ( 4 ) 1125 - 1138 2020

ISSN 02683768

© 2020, Springer-Verlag London Ltd., part of Springer Nature. It has been previously reported that electrical discharge machining (EDM) performance can be improved by tool electrode vibration. However, the mechanism of vibration-assisted EDM has not been clarified and the optimal vibration condition remains unknown due to the difficulty in direct process observation. In this study, direct observation of the EDM gap by using a high-speed video camera through a transparent workpiece electrode made of single-crystal 4H-SiC was attempted. It was found that tool vibration caused discharge dispersion and discharge frequency increase, and this tendency was more significant at higher amplitudes and higher frequencies. In addition, tool vibration-induced periodic discharge was observed, which prevented concentrated discharge and short-circuiting. Accordingly, the machining speed was improved and surface roughness was reduced. This study succeeded for the first time in observing the discharge behaviors in vibration-assisted EDM, thus revealed the effects of key parameters for process optimization.

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Surface formation behaviors in wavy microgroove cutting on various workpiece materials

Terabayashi T., Yan J.

International Journal of Automation Technology (International Journal of Automation Technology) 14 ( 2 ) 245 - 252 2020

ISSN 18817629

© 2020, Fuji Technology Press. All rights reserved. Functional films with multi-directional wavy microgrooves can be applied to reduce fluid drag in turbulent flow applications. For high-efficiency mass production of functional films through polymer imprinting, it is necessary to machine wavy microgrooves on the surfaces of metal roll molds. When wavy grooves are cut, to reduce the follow-up errors of machine tools, a very low cutting speed is normally used, but the mechanism of this cutting is still unclear. In this study, microgrooving experiments were conducted on three different workpiece materials: brass, oxygen free copper, and aluminum alloy, and their cutting mechanisms were investigated. Distinct differences in chip formation behavior and machined surface integrity were identified among these materials. Aluminum alloy was chosen as the most suitable material for roll mold fabrication. Two-directional wavy microgrooves with form accuracy on 1 µm level and surface roughness of less than 10 nm Ra were obtained.

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Influence of Wax Lubrication on Cutting Performance of Single-Crystal Silicon in Ultraprecision Microgrooving

Ameli Kalkhoran S.N., Vahdati M., Zhang Z., Yan J.

International Journal of Precision Engineering and Manufacturing - Green Technology (International Journal of Precision Engineering and Manufacturing - Green Technology) 8 ( 2 ) 611 - 624 2020

ISSN 22886206

© 2020, Korean Society for Precision Engineering. Lubrication can improve the tool-workpiece interface condition in ultraprecision machining, especially in microgrooving processes. The aim of this study was to compare the effects of dry, liquid (cutting oil), solid (wax) and hybrid (cutting oil and wax) lubrication conditions, on the creation of arc-sectioned microgrooves on single-crystal silicon wafers using a single-crystal diamond tool. Micro cutting forces, chip morphology, and surface quality at different locations of the grooves were investigated. Rose-shaped continuous chips were observed in dry cutting, indicating stable ductile mode material removal. The entrance side of the groove was always smoother than the exit side with a higher degree of phase transformation. Chip adhesions on the tool edge were found in dry and oil lubricated cutting, whereas wax coating could prevent the adhesion. Wax coating played the dual roles of a chip breaker as well as a high-performance lubricant, thus improved the surface integrity. This study demonstrated the capability of using wax coating as an environmentally friendly solid lubricant for microgrooving of single-crystal silicon and possibly for other hard brittle materials.

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Manufacturing of multiscale structured surfaces

Brinksmeier E., Karpuschewski B., Yan J., Schönemann L.

CIRP Annals (CIRP Annals) 69 ( 2 ) 717 - 739 2020

ISSN 00078506

© 2020 Multiscale structured surfaces are a way to provide advanced, otherwise not attainable functionality on a technical part. Applications of such parts can be manifold, and numerous works have already covered the transfer of natural examples into bio-inspired surfaces or the geometrical and functional metrology of such surfaces. After briefly presenting typical functionalities of multiscale structured surfaces, this keynote paper will focus on the available manufacturing processes and review their capabilities to generate multiscale structured surfaces. To compare such processes, the so-called “multiscality” is defined that characterizes the structured surfaces according to the lateral and vertical extent of the individual stacked elements and is used as a first indicator to assess the difficulty of their manufacture. As the boundaries of what is considered a multiscale structure are diffuse, ranges of low, medium and high multiscality are defined instead. After presenting the state of the art of manufacturing processes currently utilized for the manufacture of (not only multiscale) structured surfaces, this keynote paper summarizes the capabilities of single-step and multi-step/multi-physics approaches for their applicability across different scales and gives an outlook on which processes could potentially become relevant in the future.

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Measurement and compensation of tool contour error using white light interferometry for ultra-precision diamond turning of freeform surfaces

Nagayama K., Yan J.

International Journal of Automation Technology (International Journal of Automation Technology) 14 ( 4 ) 654 - 664 2020

ISSN 18817629

© 2020, Fuji Technology Press. All rights reserved. In ultra-precision diamond turning of freeform optics, it is necessary to obtain submicron-level form accuracy with high efficiency. In this study, we proposed a new method for the quick measurement and compensation of tool contour errors to improve the form accuracy of the workpiece. In this method, the nanometer-scale contour error of a diamond tool is quickly and precisely measured using a white light interferometer and then compensated for, before machining. Results showed that the contour of a diamond tool was measured with an error less than 0.05 μm peak-to-valley (P-V) and the feasibility of error compensation was verified through cutting experiments to create a paraboloid mirror and a microlens array. The form error decreased to 0.2 μm P-V regardless of the contour error of the diamond tools when cutting the paraboloid mirror, and that of the microlens array was reduced to 0.15 μm P-V during a single machining step.

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Surface modification of tungsten carbide cobalt by electrical discharge coating with quarry dust suspension

Yap C.Y., Liew P.J., Yan J.

International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 111 ( 7-8 ) 2105 - 2116 2020

ISSN 02683768

© 2020, Springer-Verlag London Ltd., part of Springer Nature. This study explores the feasibility of reusing waste quarry dust as a coating material for surface modification of tungsten carbide cobalt (WC-Co) using electrical discharge coating (EDC). The main objective is to investigate the effect of quarry dust suspension with different concentrations (0–40 g/l) on the characteristics of coated surface such as coating layer thickness, coating element composition and chemical compound, surface morphology, surface roughness and Vickers micro-hardness. Before the EDC process, characterisation of the raw quarry dust was conducted through scanning electron microscopy, X-ray fluorescence and particle size analyser. The results showed that the coating layer thickness was strongly affected by the quarry dust concentration. The formation of hard carbides (SiC, Mg2C3, Fe2C and CaC2) and oxide phases (SiO2, Al2O3, Fe2O3, CaO, CoO and ZnO) in the coated layer due to material migration was confirmed through X-ray diffraction analysis. Vickers micro-hardness of the coated surface was improved significantly with the addition of quarry dust. The best surface finish without micropores and microcracks was obtained using a quarry dust concentration of 10 g/l. These results demonstrated the capability of recycling quarry dust as an environmentally friendly coating material for surface modification.

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New evidences for understanding the serrated flow and shear band behavior in nanoindentation of metallic glasses

Huang H., Jiang M., Yan J.

Journal of Alloys and Compounds (Journal of Alloys and Compounds) 857 2020

ISSN 09258388

© 2020 Elsevier B.V. Nanoindentation of a Zr-based metallic glass was performed under various loading rates by using a cube-corner indenter. Experimental results showed that increasing the loading rate from 2 to 20 mN/s, the size of serrated flow was greatly weakened, but the number of serrated flow kept very stable, together with very similar shear band features around the residual indents. These results challenge the current understanding derived from the results obtained by using the Berkovich indenter, and can be well explained by the shear-band propagation dynamics model, i.e., loading rate impeded the propagation of shear band rather than its nucleation.

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Effects of cyclic loading on subsurface microstructural changes of zirconia polycrystals in nanoscale mechanical processing

Kosai K., Yan J.

International Journal of Machine Tools and Manufacture (International Journal of Machine Tools and Manufacture) 159 2020

ISSN 08906955

© 2020 Elsevier Ltd Yttria stabilized zirconia (YSZ) is an attractive biomaterial with excellent properties, but its deformation mechanism under repetitive loads is still unclear. In this study, the subsurface microstructural changes of YSZ polycrystals under repetitive loading/unloading were investigated by multi-cyclic nanoindentation. Raman spectroscopy analysis revealed that a tetragonal-to-monoclinic (t-m) phase transformation occurred, and multi-cyclic indentation promoted this transformation significantly. Cross-sectional scanning transmission electron microscopy showed that monoclinic variants were extensively generated beneath the free surfaces outside the indent planes, whereas grain refinement was dominant beneath the indenter tip. In addition, load-displacement curve analysis demonstrated that the t-m phase transformation occurred during unloading rather than loading, and that the phase transformation-induced volume expansion caused an incremental change of residual indent depth. The extension of monoclinic variants was promoted by repetitive shear deformation, resulting in significant pileups, as detected by atomic force microscopy. The effect of sample surface preprocessing on indentation behaviors was also investigated. Microcracking and surface spalling were confirmed around the multi-cyclic indents made on a diamond-turned YSZ sample. Based on the experimental results, a model of subsurface microstructure distribution and evolution was established. The findings from this study help clarify the historical effects in subsurface damaging mechanism of brittle polycrystalline materials caused by cyclic tool-workpiece interactions in nanoscale mechanical processing.

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Softening and hardening on a Zr-based bulk metallic glass induced by nanosecond laser surface melting

Jiao Y., Brousseau E., Kosai K., Lunt A.J.G., Yan J., Han Q., Zhu H., Bigot S., He W.

Materials Science and Engineering A (Materials Science and Engineering A) 803 2020

ISSN 09215093

© 2020 Elsevier B.V. The study reported here confirms that laser surface melting (LSM) can be employed to modify the hardness and the shear banding behaviour of bulk metallic glasses (BMGs). More specifically, by conducting LSM operations on the Zr-based Vitreloy 105 BMG in ambient atmosphere using a nanosecond laser, it was found that surface hardening can be achieved, in addition to the well-known surface softening effect. Besides, it was found that the presence of compressive residual stress and an increased introduction of crystalline precipitates accompanied LSM-induced surface hardening. On the contrary, tensile residual stress and a reduced fraction of crystalline precipitates were observed for a softened surface post-LSM. Finally, differences in shear-banding mechanisms were detected near the surface of the laser irradiated regions. More specifically, overall reduced serrated flow but important surface shear bands events were observed following the LSM-based introduction of compressive residual stress. In contrast, more pronounced serrated flows and the likely distribution of shear banding activity well beneath the irradiated BMG surface was promoted when LSM resulted in the introduction of tensile residual stress.

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Laser induced micro-cracking of Zr-based metallic glass using 1011 W/m2 nano-pulses

H Huang, Y Qian, C Wang, J Yan

Materials Today Communications 25, 101554 2020

Distortion measurement of optical system using phase diffractive beam splitter

Wang F., Zhang Z., Wang R., Zeng X., Yang X., Lv S., Zhang F., Xue D., Yan J., Zhang X.

Optics Express (Optics Express) 27 ( 21 ) 29803 - 29816 2019.10

© 2019 Optical Society of America Traditional methods for distortion measurement of large-aperture optical systems are time-consuming and ineffective because they require each field of view to be individually measured using a high-precision rotating platform. In this study, a new method that uses a phase diffractive beam splitter (DBS) is proposed to measure the distortion of optical systems, which has great potential application for the large-aperture optical system. The proposed method has a very high degree of accuracy and is extremely economical. A high-precision calibration method is proposed to measure the angular distribution of the DBS. The uncertainty analysis of the factors involved in the measurement process has been performed to highlight the low level of errors in the measurement methodology. Results show that high-precision measurements of the focal length and distortion were successfully achieved with high efficiency. The proposed method can be used for large-aperture wide-angle optical systems such as those used for aerial mapping applications.

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Effect of the pillar size on the electrochemical performance of laser-induced silicon micropillars as anodes for lithium-ion batteries

Yang X., Tachikawa N., Katayama Y., Li L., Yan J.

Applied Sciences (Switzerland) (Applied Sciences (Switzerland)) 9 ( 17 ) 2019.09

© 2019 by the authors. Silicon micropillars with tunable sizes are successfully fabricated on copper foils by using nanosecond-pulsed laser irradiation and then used as anodes for lithium-ion batteries. The size of the silicon micropillars is manipulated by using different slurry layer thicknesses ranging from a few microns to tens of microns. The effects of the pillar size on electrochemical properties are thoroughly investigated. The smaller the pillars, the better the electrochemical performance. A capacity of 1647 mAh g-1 at 0.1 C current rate is achieved in the anode with the smallest pillars, with 1215, 892, and 582 mAh g-1 at 0.2, 0.5, and 1.0 C, respectively. Although a significant difference in discharge capacity is observed in the early period of cycling among micropillars of different sizes, this discrepancy becomes smaller as a function of the cycle number. Morphological studies reveal that the expansion of micropillars occurred during long-term cycling, which finally led to the formation of island-like structures. Also, the formation of a solid electrolyte interphase film obstructs Li+ diffusion into Si for lithiation, resulting in capacity decay. This study demonstrates the importance of minimizing the pillar size and optimizing the pillar density during anode fabrication.

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Improving the surface integrity of additive-manufactured metal parts by ultrasonic vibration-assisted burnishing

Teramachi A., Yan J.

Journal of Micro and Nano-Manufacturing (Journal of Micro and Nano-Manufacturing) 7 ( 2 ) 2019.06

ISSN 21660468

Copyright © 2019 by ASME. Metal additive manufacturing (AM) has been attracting attention as a new manufacturing method, but a surface finishing process is usually needed to improve the surface quality. As a new surface finishing process, ultrasonic vibration-assisted burnishing (UVAB) is promising. In this study, UVAB was performed on an additive-manufactured AlSi10Mg workpiece to improve its surface/subsurface integrity. The effects of ultrasonic vibration (UV) and lateral tool pass width on the burnishing performance were investigated. It was observed that the surface roughness, filling ratio, and hardness of the surface layer were simultaneously improved after burnishing. This study shows the effectiveness of applying UVAB to improve the surface quality of additivemanufactured products for various industrial uses.

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Manufacturing technologies toward extreme precision

Zhang Z., Yan J., Kuriyagawa T.

International Journal of Extreme Manufacturing (International Journal of Extreme Manufacturing) 1 ( 2 ) 2019.06

ISSN 26318644

© 2019 The Author(s). Published by IOP Publishing Ltd on behalf of the IMMT Precision is one of the most important aspects of manufacturing. High precision creates high quality, high performance, exchangeability, reliability, and added value for industrial products. Over the past decades, remarkable advances have been achieved in the area of high-precision manufacturing technologies, where the form accuracy approaches the nanometer level and surface roughness the atomic level. These extremely high precision manufacturing technologies enable the development of high-performance optical elements, semiconductor substrates, biomedical parts, and so on, thereby enhancing the ability of human beings to explore the macro- and microscopic mysteries and potentialities of the natural world. In this paper, state-of-the-art high-precision material removal manufacturing technologies, especially ultraprecision cutting, grinding, deterministic form correction polishing, and supersmooth polishing, are reviewed and compared with insights into their principles, methodologies, and applications. The key issues in extreme precision manufacturing that should be considered for future R&D are discussed.

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Ultra-precision cutting of roll molds having two-directional wavy microstructures

T. Terabayashi, J. Yan

Transactions of the JSME 85 ( 874 ) 1-18 2019.06

Research paper (scientific journal), Joint Work, Accepted

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Formation behavior of laser-induced periodic surface structures on stainless tool steel in various media

Kobayashi T., Wakabayashi T., Takushima Y., Yan J.

Precision Engineering (Precision Engineering) 57 244 - 252 2019.05

ISSN 01416359

© 2019 Elsevier Inc. The formation of laser-induced periodic surface structure (LIPSS) has been observed on various materials. As LIPSS can be used for modifying various surface properties such as wettability, tribology and optical performance, the control of the period and topography of LIPSS is an important issue. In this study, picosecond pulsed laser irradiation was performed on a stainless tool steel in various types of media including the air, water, sugar syrup (water and sucrose (C 12 H 22 O 11 )), decane (C 10 H 22 ), and ethanol (C 2 H 5 OH). Different surface morphologies were observed on the steel surface after laser irradiation, depending on the types of media. A strong relationship was identified between the period of LIPSS and the refractive index of liquid. In addition to the change of LIPSS period, complicated mesh patterns were formed on the surface irradiated in decane and ethanol, indicating the significant effect of thermal conductivity of the liquids on surface formation mechanisms. This study demonstrated the possibility of controlling the period and topography of LIPSS by using different media.

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Direct observations of multi-cyclic nanoindentation-induced phase transformations in single-crystal Ge

Kosai K., Yan J.

Materials Research Express (Materials Research Express) 6 ( 7 ) 2019.04

© 2019 IOP Publishing Ltd. Multi-cyclic nanoindentation experiments with various holding loads were carried out on single-crystal Ge to investigate pressure-induced phase transformation behaviors. Cross-sectional transmission electron microscopic observation and laser micro-Raman spectroscopy of the indents revealed various phase transformation behaviors at different holding loads. Distinctive phase transformation behaviors were observed under various loading and unloading conditions. With a low holding load, a broad phase transformed region containing r8-Ge phase and dislocations was generated. A middle holding load promoted twinning but limited phase transformations. On the other hand, a densely transformed region containing dc-Ge, a-Ge, r8-Ge and st12-Ge was widely formed at a high holding load. In addition, the calculation results of the average contact pressure in the last unloading step verified the occurrence of these phase transformations. By integrating these results, a path diagram for phase transformations of single-crystal Ge during multi-cyclic nanoindentation was established, which is useful for understanding the subsurface damage formation in mechanical processing of the material.

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Investigation on wear modes and mechanisms of abrasive belts in grinding of U71Mn steel

Z. He, J. Li, Y. Liu, J. Yan

The International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 101 ( 5-8 ) 1821 - 1835 2019.04

Research paper (scientific journal), Joint Work, Accepted, ISSN 02683768

© 2018, Springer-Verlag London Ltd., part of Springer Nature. We investigated the wear modes and mechanisms of alumina grits during abrasive belt grinding of U71Mn steel under various normal forces and grinding speeds. Our approach consisted of an experimental procedure that produced sufficient wear followed by a resin-embedding method for observing the cross sections and topographies of grits. Statistics of wear modes and protrusion heights were calculated to visualize and quantify abrasive belt wear. The results demonstrated that different subsurface structures emerged inside the worn grits, and these structures were sensitive to process parameters. Transitions between abrasion and fracture wear modes were frequently observed. The effects of abrasive belt wear and process parameters on wear modes were clarified. The critical protrusion height of the abrasive belts for each wear mode of abrasive grits was experimentally determined.

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Fabrication of polycrystalline diamond three-dimensional structures by sinking EDM using carbon diffusion reaction

S. Kasai, T. Sodetai, J. Yan

Journal of the Japan Society of Electrical-machining Engineers 53 ( 132 ) 5 - 11 2019.03

Research paper (scientific journal), Joint Work, Accepted

Ultrasonic vibration-assisted microgrinding of glassy carbon

P. Beiring, J. Yan

Research paper (scientific journal), Joint Work, Accepted, ISSN 09544062

© IMechE 2019. Glassy carbon is an amorphous material which, due to its unique material properties, has recently been introduced to micro/nanoimprinting as mold substrates. However, since glassy carbon is a hard, brittle, and highly elastic material, the precision machining of micro/nanostructures on it remains a challenging task. In this research, ultrasonic vibration-assisted microgrinding was proposed for ductile machining of glassy carbon. To find suitable conditions, the effects of ultrasonic vibration assistance and tool inclination were investigated. The results showed that by utilizing ultrasonic vibration assistance and tool inclination, a ductile response was achieved with improved surface roughness. In addition, the periodical waviness of the groove edge due to material elastic recovery was successfully prevented. This study provided an insight into the kinematics in ultrasonic vibration-assisted grinding of a highly elastic, hard, and brittle material.

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Electrical Discharge Machining and Grinding of SiC Single Crystal Using a Disc-type Hybrid Tool of Polycrystalline Diamond

T. Kurosawa, J. Yan

Journal of the Japan Society of Electrical-machining Engineers 53 ( 132 ) 12 - 18 2019.03

Research paper (scientific journal), Joint Work, Accepted

Laser recovery of grinding-induced subsurface damage in the edge and notch of a single-crystal silicon wafer

K Niitsu, Y Tayama, T Kato, J. Yan

Surface Topography: Metrology and Properties (Surface Topography: Metrology and Properties) 7 ( 015013 ) 1 - 13 2019.02

Research paper (scientific journal), Joint Work, Accepted

© 2019 IOP Publishing Ltd. The edges and notches of silicon wafers are usually machined by diamond grinding, and the grinding-induced subsurface damage causes wafer breakage and particle contamination problems. However, the edge and notch surfaces have large curvature and sharp corners, thus it is difficult to be finished by chemo-mechanical polishing. In this study, a nanosecond pulsed Nd:YAG laser was used to irradiate the edge and notch of a boron-doped single-crystal silicon wafer to recover the grinding-induced subsurface damage. The reflection loss and the change of laser fluence when irradiating a curved surface were considered, and the damage recovery behavior was investigated. The surface roughness, crystallinity, and hardness of the laser recovered region were measured by using white light interferometry, laser micro-Raman spectroscopy, and nanoindentation, respectively. The results showed that after laser irradiation the damaged region was recovered to a single-crystal structure with nanometric surface roughness, and the surface hardness was also improved. This study demonstrates that laser recovery is a promising post-grinding process for improving the surface integrity of the edge and notch of silicon wafers.

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Effects of tool rake angle and tool nose radius on surface quality of ultraprecision diamond-turned porous silicon

M. Heidari, J. Akbari, J. Yan

Journal of Manufacturing Processes (Journal of Manufacturing Processes) 37 321 - 331 2019.01

Research paper (scientific journal), Joint Work, Accepted, ISSN 15266125

© 2018 The Society of Manufacturing Engineers This paper presents an investigation of the effects of tool rake angle and nose radius on the surface quality of ultraprecision diamond-turned porous silicon. The results showed that as rake angle decreases, the high-stress field induced by the tool edge increases, causing microcracks to propagate extensively near the pore walls. As a result, the ductile-machined areas shrank under a negative tool rake angle. On the other hand, brittle fracture occurred around pores released cutting pressure significantly. These trends of rake angle effects are distinctly different from those in the cutting of non-porous silicon. Finite element simulation of stress in the cutting area agreed with the experimental results. The results also indicated that using a tool with a bigger nose radius suppressed brittle fractures around the pore edge and improved surface quality. Raman spectroscopy of the ductile-machined surfaces revealed that the amorphization of the subsurface layer became more significant when decreasing tool rake angle or increasing tool nose radius. By choosing the optimal tool geometry, a high quality surface can be achieved on porous silicon, which demonstrates the capability of the diamond turning process to fabricate high-precision components.

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Investigation of Ultra-Precision Machining on Single Crystal Silicon Using Molecular Dynamics Simulation and Experiments

SN Ameli Kalkhoran, M Vahdati, J Yan

Amirkabir Journal of Mechanical Engineering 52 (3), 731-742 2019

Single-grain cutting based modeling of abrasive belt wear in cylindrical grinding

He Z., Li J., Liu Y., Yan J.

Friction (Friction) 8 ( 1 ) 208 - 220 2019

ISSN 22237690

© 2019, The Author(s). A systematic wear model of the cylindrical grinding process with an alumina abrasive belt from the perspective of single grain sliding wear was established in this study. The model consists of three parts: a single cutting force model derived by applying a stress integration method, a single grain wear height analysis based on the wear rate of alumina, and a grinding mileage prediction of multiple grains with Gaussian distributed protrusion heights. Cutting force, single grain wear height and full-size grinding mileage verification experiments were conducted. The results indicated that the established model was in reasonable agreement with the experimental outcomes, which suggests that this model could be useful in the industry to predict the wear process of abrasive belts.

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Chip morphology and surface integrity in ultraprecision cutting of yttria-stabilized tetragonal zirconia polycrystal

Yan J., Okuuchi T.

CIRP Annals 2019

ISSN 00078506

© 2019 Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) is an important material for dental, biomedical, and mechanical applications. In this study, Y-TZP was cut by a single-crystal diamond tool in the micro-nanometre scale. The chip morphology and machined surface/subsurface properties under various conditions were investigated by scanning electron microscopy, Raman spectroscopy and cross-sectional transmission electron microscopy. Two factors dominating the material removal were identified: (i) crystal grain refinement and (ii) tetragonal-to-monoclinic phase transformation, the mechanisms of which were established by experiments and finite element simulations. This study provides a possible solution to the rapid fabrication of small 3D features on Y-TZP with nanometric surface roughness and an ultra-fine-grained subsurface layer.

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Molecular Dynamics Investigation of Nanometric Cutting of Single-Crystal Silicon Using a Blunt Tool

Ameli Kalkhoran S., Vahdati M., Yan J.

JOM (JOM) 71 ( 12 ) 4296 - 4304 2019

ISSN 10474838

© 2019, The Minerals, Metals & Materials Society. A cutting process is strongly affected by depth of cut (h0) and tool edge radius (re), the relationship of which is described by relative tool sharpness (RTS = h0/re). In nanometric cutting, the depth of cut is far smaller than the tool edge radius, thus the tool is actually a very blunt one with a highly negative effective tool rake angle (~ − 90°). However, most previous studies have assumed the tool is extremely sharp with a nanometric edge radius, and to date there is very little literature on the cutting mechanism for a blunt tool (RTS < 1). In this study, the material deformation/removal behavior and forces under a small RTS from 1 to 0 were investigated via molecular dynamics. The results show that the surface integrity and chip formation are strongly affected by RTS. As RTS is reduced to 0.25 or smaller, rubbing and ploughing occur with no material removal. In such a circumstance, the force angle drops sharply with remarkable subsurface damage formation in the workpiece. These findings are distinctly different from the common belief, and provide new information for the optimization of the silicon wafer manufacturing process.

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Generation of microcones on reaction-bonded silicon carbide by nanosecond pulsed laser irradiation

Meshram T., Yan J.

International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 108 ( 4 ) 1039 - 1048 2019

ISSN 02683768

© 2019, Springer-Verlag London Ltd., part of Springer Nature. Silicon carbide (SiC) is heavily used in the industry due to its resistance to chemical wear and excellent mechanical properties such as high hardness and high stiffness. However, these properties make it difficult to produce micro and nanostructures on the surface of SiC by conventional methods. In this study, high-density microcones that protrude ~ 10 μm above the initial surface have been fabricated by nanosecond pulsed Nd:YAG laser irradiation (λ = 532 nm) on reaction-bonded SiC. Geometrically aligned cones were also fabricated by modifying the laser scanning path, and effect of different parameters such as pulse frequency, laser fluence was studied. It was observed that the surface morphology of microcones was affected by the pulse width and beam overlap. X-ray spectroscopy and Raman spectroscopy showed that the microcones were mainly composed of silicon. Formation of these cone structures made the surface highly superhydrophilic with a contact angle of ~ 0°.

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Study on infrared transmittance of si-polymer hybrid structure press molded using a coupling agent

Ishide H., Yan J.

International Journal of Automation Technology (International Journal of Automation Technology) 13 ( 6 ) 817 - 824 2019

ISSN 18817629

© 2019, Fuji Technology Press. All rights reserved. Hybrid structures of single-crystal silicon and high-density polyethylene (HDPE) with high transmittance in the mid-to-far infrared region are used as infrared lens substrates. The hybrids are usually fabricated by high-precision press molding. The Si-HDPE hybrid lens previously fabricated had a low transmittance in the 9–10 μm wavelength region, thereby limiting its application for human body detection. In this study, a Si-polymer hybrid structure was fabricated using a new polymer without any silane coupling agent. Interfacial adhesion between the polymer and the Si substrate was realized with an extremely thin (a few micron thick) layer of an interfacial silane coupling agent. The press molding conditions that led to improved bonding strength and infrared transmittance of the hybrid substrate were investigated. A transmittance similar to that of a single-crystal Si substrate was achieved in the 9–10 μm wavelength range.

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Fabrication of porous composite by high-pressure sintering of silicon cutting chips and metal particles

Y. Sunaba, N. Tachikawa, Y. Katayama, J. Yan

Journal of the Japan Society for Abrasive Technology 62 ( 11 ) 584 - 588 2018.11

Research paper (scientific journal), Joint Work, Accepted

Experimental investigation of RB-SiC using Cu–CNF composite electrodes in electrical discharge machining

P. J. Liew, Z. Nurlishafiqa, Q. Ahsan, T. Zhou, J. Yan

The International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 98 ( 9-12 ) 3019 - 3028 2018.10

Research paper (scientific journal), Joint Work, Accepted, ISSN 02683768

© 2018, Springer-Verlag London Ltd., part of Springer Nature. The performances of carbon nanofiber (CNF) reinforced copper (Cu) composite electrodes on the reaction-bonded silicon carbide (RB-SiC) ceramic were experimentally investigated by using electrical discharge machining (EDM). The effects of CNF content on material removal rate (MRR), electrode wear ratio (EWR), surface roughness (SR) and surface topography were examined. Results indicated that the addition of CNF to the Cu electrode increased the MRR of the workpiece. In addition, increasing the added CNF content increased the EWR of the Cu–CNF composite electrode and the SR of the machined surface. The results of one-way ANOVA indicated that the Cu–1.0 wt% CNF composite electrode exhibited the optimal MRR and EWR values, although this electrode resulted the maximum SR on the RB-SiC machined surface.

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Surface flattening and nanostructuring of steel by picosecond pulsed laser irradiation

T. Kobayashi, H. Sera, T. Wakabayashi, H. Endo, Y. Takushima, J. Yan

Nanomanufacturing and Metrology (Nanomanufacturing and Metrology) 1 ( 4 ) 217 - 224 2018.09

Research paper (scientific journal), Joint Work, Accepted, ISSN 2520811X

© 2018, International Society for Nanomanufacturing and Tianjin University and Springer Nature. Steel is used as a mold material for press/injection molding of plastic products. High accuracy and releasing ability are required for a steel mold surface. This paper proposes a surface finishing method for steel molds by using picosecond pulsed laser irradiation. The process involves two steps: one is surface flattening by removing the surface asperity through laser ablation, and the other is forming nanoscale laser-induced periodic surface structures (LIPSS) on the flattened surface. The two steps are realized by using the same laser at controlled laser fluence and focus position. Experimental results showed that LIPSS was successfully formed after surface flattening under specific ranges of laser fluence and defocus length. Furthermore, plastic forming experiments demonstrated that a steel surface with LIPSS significantly decreased the effective contact area and, in turn, reduced the mold releasing force. These findings provide the possibility of fabricating high-performance steel molds by picosecond pulsed laser irradiation.

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Surface Roughness in Ultrasonic-Assisted and Conventional Milling of Soda-Lime Glass

Y. El-Taybany, M. Hossam, J. Yan, H. El-Hofy

International Journal of Machining and Machinability of Materials (International Journal of Machining and Machinability of Materials) 20 ( 1-2 ) 82 - 99 2018.09

Research paper (scientific journal), Joint Work, Accepted, ISSN 17485711

© 2019 Inderscience. All Rights Reserved. Glass has an increasing demand in many industrial fields such as micro-channels and micro reactors in fluidic applications, lab-on-a-chip in medical applications, and micro lens arrays and optical devices. Machining of glass as one of hard-to-machine materials is challengeable due to its distinctive properties of high strength, hardness, and brittleness. Facing these challenges, ultrasonic-assisted milling (UAM); an advanced machining process; was provided for its effectiveness in machining such hard-to-machine materials. In this paper, the effects of feed rate, depth of cut, ultrasonic-vibration assistance, and cutting fluid on surface roughness in UAM of soda-lime glass compared with conventional milling (CM) were investigated. Results showed that, by introducing ultrasonic-vibration, higher surface roughness was obtained. The optimal cutting conditions were attained using response surface methodology. At the optimised parametric setting, the minimum surface roughness was found to be at wet conventional milling.

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The coupling effects of laser thermal shock and surface nitridation on mechanical properties of Zr-based metallic glass

H. Huang, M. Jiang, J. Yan

Journal of Alloys and Compounds (Journal of Alloys and Compounds) 770 864 - 874 2018.06

Research paper (scientific journal), Joint Work, Accepted, ISSN 09258388

© 2018 Elsevier B.V. Laser processing is a versatile tool for applications in the field of metallic glasses (MGs). Previous studies reported that surface nitridation, i.e. the formation of ZrN phase, occurred when laser irradiation of Zr-based MG was performed in nitrogen gas. Additionally, it was reported that laser thermal shock usually softened the irradiated surface. Therefore, the coupling effects of laser thermal shock and surface nitridation on mechanical characteristics of Zr-based MG should be further clarified. For this purpose, in this study, laser irradiation of Zr-based MG was conducted under various experimental conditions, followed by evaluating the surface characteristics by X-ray diffraction (XRD), nanoindentation, and energy-dispersive X-ray (EDX) spectroscopy. Experimental results indicated that the nanoindentation hardness, serrated flow, and surface shear bands were significantly affected by laser irradiation in nitrogen gas. Both surface softening and hardening were observed which depended on the experimental conditions. A competition mechanism between laser thermal shock and the introduction of ZrN phase was employed to rationalize these results. Furthermore, the affecting layer of ZrN phase along the depth direction was measured by EDX. The obtained results suggest a new method to introduce secondary phase into Zr-based MG surface and further to tune the mechanical characteristics of MGs.

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Multi-scale dimple creation on metallic glass by a two-step method involving nanoindentation and polishing

H. Huang, J. Yan

Applied Surface Science (Applied Surface Science) 462 565 - 574 2018.06

Research paper (scientific journal), Joint Work, Accepted, ISSN 01694332

© 2018 Elsevier B.V. Creation of micro dimples on material surface is significant for their functional applications. Because of unique properties, metallic glasses are regarded as emerging structural and functional materials but they are also a kind of difficult-to-cut materials due to high hardness and easy to crystallization and oxidation. In this study, a new method was proposed to fabricate micro dimples on metallic glass surface, which consisted of two steps, nanoindentation experiments to form the pre-indent array followed by polishing. Via this two-step method, square and rectangle dimples were successfully formed which exhibited multi-scale features with one relatively large dimple with width in micron-scale and depth in nanometer-scale, together with relatively small residual indents in nanometer-scale distributed on its bottom surface. The experimental results indicated that the depth of multi-scale dimples was affected by the spatial interval between two indents and the polishing time. Under the used experimental conditions, for the same polishing time, the depth of the large dimple was decreased when increasing the interval; for the same interval, with increase in the polishing time, the depth of the large dimple was also decreased. The possible formation mechanism of the large dimple was discussed, which was mainly ascribed to the enhanced material removal at the position of pre-indent array because of the concentration of polishing particles by the pre-indents.

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Material removal mechanism and surface integrity in ultraprecision cutting of porous titanium

M. Heidari, J. Yan

Precision Engineering (Precision Engineering) 52 356 - 369 2018.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 01416359

© 2018 Elsevier Inc. Porous titanium presents unique material properties with a wide variety of mechanical and biomedical applications. Porous titanium components fabricated by near net-shape technologies require further machining processes to improve the surface quality and form accuracy, and in turn, the added value of the products. In this work, major factors dominating the surface integrity in ultraprecision cutting of porous titanium using single-crystal diamond tools were investigated. The results demonstrated that the presence of pores significantly changed mechanism of cutting. The chip morphology and surface topography depended on pore size and undeformed chip thickness. At an extremely small undeformed chip thickness, a majority pores were closed due to the welding phenomenon, leading to a sharp drop of surface porosity. In contrast, large pores cause craters on the machined surface and segmentation of chips and protruding lamella, especially at a large undeformed chip thickness. A coolant could lubricate the tool-workpiece interface and the shear deformation, which decreased cutting forces. On the other hand, the rapid cooling effect enhanced the work hardening effect and increase the hardness of the machined surface. Tool wear in cutting porous titanium is suppressed compared with that of pure titanium, especially in wet cutting.

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Nanosecond pulsed laser irradiation of sapphire for developing microstructures with deep V-shaped grooves

N. Takayama, S. Asaka, J. Yan

Precision Engineering (Precision Engineering) 52 440 - 450 2018.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 01416359

© 2018 Elsevier Inc. A nanosecond pulsed Nd:YAG laser was used to irradiate a sapphire substrate to produce 3-dimensional microstructures with sharp V-shaped grooves. In initial experiments, where single grooves were machined, a maximum taper angle of ∼79° was obtained. At constant laser parameters, the taper angle remained constant. As the taper angle increases from a flat surface, the irradiated area increases while incident fluence decreases; once the incident fluence approaches the ablation threshold, the taper angle becomes constant. The taper angle could be controlled by the laser fluence, scanning speed and incident angle of the laser beam. Using these results, a kind of surface microstructure, comprised of micropyramids with steep walls, was successfully machined for optical measurement applications. The surface roughness, transmittance and crystallinity of the microstructure surface could be controlled by the laser scanning speed. By applying the taper formation mechanism proposed in this study, the micromachining of sharp microstructures with steep walls on various hard brittle materials becomes possible.

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Microgrooving of a single-crystal diamond tool using a picosecond pulsed laser and some cutting tests

N. Takayama, J. Ishizuka, J. Yan

Precision Engineering (Precision Engineering) 53 252 - 262 2018.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 01416359

© 2018 Elsevier Inc. Irradiation of a single-crystal diamond tool was performed with a picosecond pulsed laser to produce a tool with a microgrooved edge. This tool was then used in a metal cutting process to transfer the edge grooves onto a workpiece. Suitable conditions for laser irradiation on the diamond tool were experimentally investigated in terms of groove shape and laser-induced damage to diamond. Two different kinds of cutting experiments were performed; a uniformly grooved surface and a hierarchically structured surface were obtained. The chip formation mechanisms in the metal grooving process were examined. A copper workpiece was rapidly machined the surface of which had microgrooves with a pitch of a few micrometers. An increase of the contact angle was observed on the grooved surface, indicating the improvement of water repellency. This study presents an efficient method to machine microgrooves on metal materials for functional surfaces.

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Nanoscale surface patterning of diamond utilizing carbon diffusion reaction with a microstructured titanium mold

J. Yan, Y. Imoto

CIRP Annals – Manufacturing Technology (CIRP Annals) 67 ( 1 ) 181 - 184 2018.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 00078506

© 2018 A novel method was proposed for generating nanoscale surface patterns on single-crystal diamond by carbon diffusion with a microstructured titanium mold under controlled temperature and pressure. The depth, geometry, and surface integrity of the fabricated patterns were investigated by laser micro-Raman spectroscopy and white-light interferometry, and the titanium molds were analyzed by energy dispersive X-ray spectroscopy. The results showed that at specific temperatures and pressures, three-dimensional patterns with a depth of tens of nanometers and sloped/curved walls could be generated on a diamond surface after a few minutes, without causing any surface graphitization. The intensity profile and penetration depth of carbon atoms into the titanium were experimentally measured.

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Softening of Zr-based metallic glass induced by nanosecond pulsed laser irradiation

H. Huang, M. Jiang, J. Yan

Journal of Alloys and Compounds (Journal of Alloys and Compounds) 754 215 - 221 2018.05

Research paper (scientific journal), Joint Work, Accepted, ISSN 09258388

© 2018 Elsevier B.V. Laser irradiation has been recently used to tune the mechanical properties of metallic glasses (MGs). However, the mechanism for plasticity improvement by laser irradiation is still not completely clear and requires further investigation. In this study, nanosecond pulsed laser irradiation is applied on a Zr-based MG surface under various laser powers, scanning speeds, and numbers of irradiation cycles. Then, the mechanical properties of the as-cast and laser-irradiated MG surfaces are characterized by nanoindentation tests. In particular, the indentation hardness, load-depth curve, serrated flow, and residual indent morphology of the surfaces are compared. The results show that the nanosecond pulsed laser irradiation softens the irradiated regions; the effect of the irradiation is slightly dependent on the laser irradiation parameters, and especially the laser scanning speed. Furthermore, laser irradiation considerably affects serrated flows in the load-depth curve and shear bands on the top surface, denoting different plastic deformation characteristics compared with the non-irradiated sample. These differences could be rationalized in terms of laser irradiation-induced formation of pre-existing shear bands in the subsurface layer, as well as thermal effects. The present results are expected to enhance the general understanding of the effects of laser irradiation on the mechanical properties of MGs.

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Noncontact on-machine measurement system based on capacitive displacement sensors for single-point diamond turning

X. Li, Z. Zhang, H. Hu, Y. Li, L. Xiong, X. Zhang, J. Yan

Optical Engineering (Optical Engineering) 57 ( 4 ) 044105 2018.04

Research paper (scientific journal), Joint Work, Accepted, ISSN 00913286

© 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). On-machine measurements can improve the form accuracy of optical surfaces in single-point diamond turning applications; however, commercially available linear variable differential transformer sensors are inaccurate and can potentially scratch the surface. We present an on-machine measurement system based on capacitive displacement sensors for high-precision optical surfaces. In the proposed system, a position-Trigger method of measurement was developed to ensure strict correspondence between the measurement points and the measurement data with no intervening time-delay. In addition, a double-sensor measurement was proposed to reduce the electric signal noise during spindle rotation. Using the proposed system, the repeatability of 80-nm peak-To-valley (PV) and 8-nm root-mean-square (RMS) was achieved through analyzing four successive measurement results. The accuracy of 109-nm PV and 14-nm RMS was obtained by comparing with the interferometer measurement result. An aluminum spherical mirror with a diameter of 300 mm was fabricated, and the resulting measured form error after one compensation cut was decreased to 254 nm in PV and 52 nm in RMS. These results confirm that the measurements of the surface form errors were successfully used to modify the cutting tool path during the compensation cut, thereby ensuring that the diamond turning process was more deterministic. In addition, the results show that the noise level was significantly reduced with the reference sensor even under a high rotational speed.

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Characterization of recrystallized depth and dopant distribution in laser recovery of grinding damage in single-crystal silicon

K. Niitsu, Y. Tayama, T. Kato, H. Maehara, J. Yan

Materials Science in Semiconductor Processing (Materials Science in Semiconductor Processing) 82 54 - 61 2018.04

Research paper (scientific journal), Joint Work, Accepted, ISSN 13698001

© 2018 Elsevier Ltd A nanosecond pulsed Nd:YAG laser was irradiated on a boron-doped single-crystal silicon wafer with a diamond grinding finish to recover the grinding-induced subsurface damage. In order to visualize and measure the depth of the laser melted/recrystallized layer, small-angle beveled polishing was performed in pure water followed by KOH etching. It enabled the direct observation of the recrystallized region using a differential interference microscope and the measurement of its depth using a white light interferometer. Crystallinity analysis of the recrystallized region was carried out by using laser micro-Raman spectroscopy, and the dopant concentration profile was characterized by using radio frequency glow discharge optical emission spectrometry (rf-GD-OES). The results showed that the crystallinity and boron distribution in the recrystallized region changed after laser recovery. The dopant concentration becomes higher at the boundary of the recrystallized region and the bulk. This study demonstrates the possibility of boron concentration control by using suitable laser parameters.

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Fracture toughness and sliding properties of magnetron sputtered CrBC and CrBCN coatings

Q. Wang, F. Zhou, Q. Ma, M. Callisti, T. Polcar, J. Yan

Applied Surface Science (Applied Surface Science) 443 635 - 643 2018.03

Research paper (scientific journal), Joint Work, Accepted, ISSN 01694332

© 2018 Elsevier B.V. CrBC and CrBCN coatings with low and high B contents were deposited on 316L steel and Si wafers using an unbalanced magnetron sputtering system. Mechanical properties including hardness (H), elastic modulus (E) and fracture toughness (K Ic ) as well as residual stresses (σ) were quantified. A clear correlation between structural, mechanical and tribological properties of coatings was found. In particular, structural analyses indicated that N incorporation in CrBC coatings with high B content caused a significant structural evolution of the nanocomposite structure (crystalline grains embedded into an amorphous matrix) from nc-CrB 2 /(a-CrB x , a-BC x ) to nc-CrN/(a-BC x , a-BN). As a result, the hardness of CrBC coating with high B content decreased from 23.4 to 16.3 GPa but the fracture toughness was enhanced. Consequently, less cracks initiated on CrBCN coatings during tribological tests, which combined with the shielding effect of a-BN on wear debris, led to a low friction coefficient and wear rate.

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Ultraprecision cutting of fluoride glass

ISHIZUKA Jun, NAGASAWA Keisuke, MIKAMI Masayuki, YAN Jiwang

Journal of the Japan Society for Abrasive Technology (The Japan Society for Abrasive Technology) 62 ( 2 ) 88 - 93 2018.02

Accepted, ISSN 0914-2703

Severe diamond tool wear may be caused by a chemical reaction between SiO2 in glass and diamond during ultraprecision cutting of silica glass, because silica glass is based on SiO2. This study demonstrated that adopting fluoride glass, which has no SiO2 constituent, as the workpiece reduced tool edge retreat to 1/22 of that of silica glass. This was because the fluoride glass contains no SiO2, which reacts chemically with diamond and leads to severe tool wear. Ductile mode cutting of fluoride glass was realized for long cutting distance. As an application, an aspherical glass lens was produced by ultraprecision cutting. In addition, the tool wear, surface generation, and chip formation mechanisms were investigated.

Ultraprecision cutting of single-crystal calcium fluoride for fabricating micro flow cells

R. Komiya, T. Kimura, T. Nomura, M. Kubo, J. Yan

Journal of Advanced Mechanical Design, Systems, and Manufacturing (Journal of Advanced Mechanical Design, Systems and Manufacturing) 12 ( 1 ) 17-00388, 1 - 13 2018.02

Research paper (scientific journal), Joint Work, Accepted

© 2018 The Japan Society of Mechanical Engineers. Single-crystal infrared (IR) spectroscopy is a promising method for protein structure analysis, where a protein crystal sample is fixed in a micro flow cell. Single-crystal calcium fluoride (CaF2) is expected as the flow cell substrate material for its excellent optical property. However, CaF2 is a highly brittle material having strong anisotropy, thus is extremely difficult to machine. Up to date, there is no available literature on fabrication of CaF2 flow cells. In this study, micro flow cells of single-crystal CaF2 were fabricated by ultraprecision cutting technology. Fly cutting was conducted using a single-crystal diamond tool having straight edges to generate a depth-varying rectangle cross section for the flow cell. The effects of cutting direction, workpiece orientation, undeformed chip thickness and tool rake angle on cutting behavior were investigated. Based on experiments and analysis, optimal conditions for ductile machining of micro grooves in CaF2 were identified. As a result, a 10 μm deep CaF2 micro flow cell with surface roughness of 2.4 nmRa was successfully fabricated. Using the fabricated flow cell, IR spectroscopic analysis of a protein single crystal at room temperature was succeeded. This study demonstrated the effectiveness of ultraprecision cutting technology in CaF2 micro flow cell fabrication, which contributes to the IR analysis of protein, and in turn, the advance of life science.

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Nanometer-scale chip formation and surface integrity of pure titanium in diamond turning

M. Heidari, J. Yan

International Journal of Advanced Manufacturing Technology (International Journal of Advanced Manufacturing Technology) 95 ( 1-4 ) 479 - 492 2018.02

Research paper (scientific journal), Joint Work, Accepted, ISSN 02683768

© 2017, Springer-Verlag London Ltd. Titanium is attracting great attentions in aerospace and medical applications where high surface quality plays an important role in improving the product performance. For developing nano-precision machining technology for titanium, clarification of the nanometer-scale chip formation mechanism is essential. In this study, the surface formation mechanism of pure titanium in ultraprecision cutting tests using single-crystal diamond tools was investigated. The results demonstrated that decreasing undeformed chip thickness from the micrometer scale down to the nanometer scale had profound impacts on the shear angle, specific cutting force, and chip morphology. Chip tearing phenomenon occurred when undeformed chip thickness is smaller than a critical value (~ 100 nm), which significantly affected the chip morphology and machined surface integrity. In nanometer-scale cutting, tool feed mark is no longer a major reason of surface roughness; instead, material plucking, debris, scratches, and chip adhesion influenced the surface integrity. The high pressure generated in the nanometer-scale cutting caused a hardness increase in workpiece material and promoted workpiece material adhesion to the tool surface, as well as tool wear.

Access to Document (DOI)

Ultraprecision cutting of fluoride glass - Fundamental investigation on surface formation and tool damage -

J. Ishizuka, K. Nagasawa, M. Mikami, J. Yan

Journal of the Japan Society for Abrasive Technology 62 ( 2 ) 88 - 93 2018.02

Research paper (scientific journal), Joint Work, Accepted

Precision slicing of single-crystal SiC using extremely fine fixed-abrasive diamond wire

T. Suzuki, T. Otsuki, J. Yan

Transactions of the JSME 84 ( 857 ) 1 - 18 2018.01

Research paper (scientific journal), Joint Work, Accepted

Comparative study of phase transformation in single-crystal germanium during single and cyclic nanoindentation

K. Kosai, H. Huang, J. Yan

Crystals 7 ( 333 ) 1 - 11 2017.11

Research paper (scientific journal), Joint Work, Accepted

Fabrication of hexagonal microlens arrays on single-crystal silicon by tool-servo segment turning method

M. Mukaida, J. Yan

Micromachines 8 ( 323 ) 1 - 18 2017.11

Research paper (scientific journal), Joint Work, Accepted

An investigation on the crack resistance of CrN, CrBN and CrTiBN coatings via nanoindentation

Q. Wang, F. Zhou, Z. Zhou, L. K-Y Li, J. Yan

Vacuum 145 186 - 193 2017.10

Research paper (scientific journal), Joint Work, Accepted

Mechanisms of material removal and subsurface damage in fixed-abrasive diamond wire slicing of single-crystalline silicon

T. Suzuki, Y. Nishino, J. Yan

Precision Engineering 50 32 - 43 2017.09

Research paper (scientific journal), Joint Work, Accepted

Effect of surfactants and additives on electrical discharge machining of Reaction Bonded Silicon Carbide

M. R. A. Razak, P. J. Liew, N. I. S. Hussein, Q. Ahsan, J. Yan

ARPN Journal of Engineering and Applied Sciences 12 ( 14 ) 4334 - 4339 2017.09

Research paper (scientific journal), Joint Work, Accepted

Investigating shear band interaction in metallic glasses by adjacent nanoindentation

H. Huang, J. Yan

Materials Science & Engineering A 704 375 - 385 2017.08

Research paper (scientific journal), Joint Work, Accepted

Fabrication of Microstructures on Single-crystal Diamond by Press Imprinting Utilizing Pure Iron Molds

Y. Imoto, J. Yan

Journal of the Japan Society for Precision Engineering 83 ( 8 ) 770 - 774 2017.08

Research paper (scientific journal), Joint Work, Accepted

Laser Irradiation Responses of a Single-Crystal Diamond Produced by Different Crystal Growth Methods

N. Takayama, J. Yan

Applied Sciences 7 ( 815 ) 1 - 15 2017.08

Research paper (scientific journal), Joint Work, Accepted

A nanosecond time-resolved XFEL analysis of structural changes associated with CO release from cytochrome c oxidase

A. Shimada, M. Kubo, S. Baba, K. Yamashita, K. Hirata, G. Ueno, T. Nomura, T. Kimura, K. Shinzawa-Itoh, J. Baba, K. Hatano, Y. Eto, A. Miyamoto, H. Murakami, T. Kumasaka, S. Owada, K. Tono, M. Yabashi, Y. Yamaguchi, S. Yanagisawa, M. Sakaguchi, T. Ogura, R. Komiya, J. Yan, E. Yamashita, M. Yamamoto, H. Ago, S. Yoshikawa, T. Tsukihara

Science Advances 3 ( e1603042 ) 1 - 12 2017.07

Research paper (scientific journal), Joint Work, Accepted

Ultraprecision surface flattening of porous silicon by diamond turning

M. Heidari, J. Yan

Precision Engineering 49 262 - 277 2017.07

Research paper (scientific journal), Joint Work, Accepted

Fabrication of single-crystal silicon micro pillars on copper foils by nanosecond pulsed laser irradiation

J. Yan, J. Noguchi, Y. Terashi

CIRP Annals – Manufacturing Technology 66 ( 1 ) 253 - 256 2017.07

Research paper (scientific journal), Joint Work, Accepted

On the phase transformation of single-crystal 4H-SiC during nanoindentation

M. Matsumoto, H. Huang, H. Harada, K. Kakimoto,　J. Yan

Journal of Physics D: Applied Physics 50 ( 265303 ) 1 - 9 2017.06

Research paper (scientific journal), Joint Work, Accepted

Surface patterning of Zr-based metallic glass by laser irradiation induced selective thermoplastic extrusion in nitrogen gas

H. Hu, J. Yan

Journal of Micromechanics and Microengineering 27 ( 075007 ) 1 - 13 2017.06

Research paper (scientific journal), Joint Work, Accepted

Thermochemical Micro Imprinting of Single-crystal Diamond Surface Using a Nickel Mold under High-Pressure Conditions

Y. Imoto, J. Yan

Applied Surface Science 404 318 - 325 2017.05

Research paper (scientific journal), Joint Work, Accepted

Mechanisms of micro-groove formation on single-crystal diamond by a nanosecond pulsed laser

N. Takayama, J. Yan

Journal of Materials Processing Technology 243 299 - 311 2017.05

Research paper (scientific journal), Joint Work, Accepted

Study on the crack resistance of CrBN composite coatings via nano-indentation and scratch tests

Q. Wang, F. Zhou, M. Callisti, T. Polcar, J. Kong, J. Yan

Journal of Alloys and Compounds 708 1103 - 1109 2017.03

Research paper (scientific journal), Joint Work, Accepted

Fundamental characteristics of material removal and surface formation in diamond turning of porous carbon

M. Heidari, J. Yan

International Journal of Additive and Subtractive Materials Manufacturing 1 ( 1 ) 23 - 41 2017.03

Research paper (scientific journal), Joint Work, Accepted

Ductile machining of single-crystal silicon for microlens arrays by ultraprecision diamond turning using a slow tool servo

M. Mukaida, J. Yan

International Journal of Machine Tools and Manufacture 115 2 - 14 2017.02

Research paper (scientific journal), Joint Work, Accepted

Improvement of glass formability in ultrasonic vibration assisted molding process

T. Zhou, J. Xie, J. Yan, T. Kuriyagawa, X. Wang

International Journal of Precision Engineering and Manufacturing 18 ( 1 ) 57-62 2017.01

Research paper (scientific journal), Joint Work, Accepted

Micropatterning of diamond crystallites via cobalt-catalyzed thermochemical etching

J. Wang, L. Wan, J. Chen, J. Yan

Journal of Materials Science 52 709 - 720 2017.01

Research paper (scientific journal), Joint Work, Accepted

Atomic-scale characterization of subsurface damage and structural changes of single-crystal silicon carbide subjected to electrical discharge machining

T.H. Tan, J. Yan

Acta Materialia 123 362 - 372 2017.01

Research paper (scientific journal), Joint Work, Accepted

Improvement of form accuracy and surface integrity of Si-HDPE hybrid micro-lens arrays in press molding

A. R. Abdul Manaf, J. Yan

Precision Engineering 47 469 - 479 2017.01

Research paper (scientific journal), Joint Work, Accepted

Design and fabrication of Si-HDPE hybrid Fresnel lenses for infrared imaging systems

A. R. Abdul Manaf, T. Sugiyama, J. Yan

Optics Express 25 ( 2 ) 1202 - 1220 2017.01

Research paper (scientific journal), Joint Work, Accepted

High-precision micro-grooving of CFRP by ultrasonic vibration-assisted grinding

T. Yamazaki, J. Yan

Journal of the Japan Society for Abrasive Technology 60 ( 12 ) 659-664 2016.12

Research paper (scientific journal), Joint Work, Accepted

Microstructural changes of Zr-based metallic glass during micro-electrical discharge machining and grinding by a sintered diamond tool

H. Huang, J. Yan

Journal of Alloys and Compounds 688 14 - 21 2016.12

Research paper (scientific journal), Joint Work, Accepted

Shield gas induced cracks during nanosecond-pulsed laser irradiation of Zr-based metallic glass

H. Huang, J. Noguchi, J. Yan

Applied Physics A 122 ( 881 ) 1 - 5 2016.12

Research paper (scientific journal), Joint Work, Accepted

Nanosecond pulsed laser irradiation induced hierarchical micro/nanostructures on Zr-based metallic glass substrate

H. Huang, J. Noguchi, M. Jiang, R. Moriya, J. Yan

Materials & Design 109 153 - 161 2016.11

Research paper (scientific journal), Joint Work, Accepted

Crack-free ductile mode grinding of fused silica under controllable dry grinding conditions

W. Wang, P. Yao, J. Wang, C. Huang, H. Zhu, B. Zou, H. Liu, J. Yan

International Journal of Machine Tools and Manufacture 109 126 - 136 2016.10

Research paper (scientific journal), Joint Work, Accepted

Effects of pre-compression deformation on nanoindentation response of Zr65Cu15Al10Ni10 bulk metallic glass

H. Huang, J. Zhang, C. H. Shek, J. Yan

Journal of Alloys and Compounds 674 ( 25 ) 223 - 228 2016.07

Research paper (scientific journal), Joint Work, Accepted

Diamond turning of high-precision roll-to-roll imprinting molds for fabricating subwavelength gratings

C-W. Liu, J. Yan, S-C. Lin

Optical Engineering 55 ( 6 ) 064105, 1 - 7 2016.06

Research paper (scientific journal), Joint Work, Accepted

Fabrication of silicon-based porous nanocomposite films by focused infrared light sintering

J. Yan, K. Okada

CIRP Annals – Manufacturing Technology 65 ( 1 ) 217 - 220 2016.06

Research paper (scientific journal), Joint Work, Accepted

Surface patterning of synthetic diamond crystallites using nickel powder

J. Wang, L. Wan, J. Chen, J. Yan

Diamond & Related Materials 66 206 - 212 2016.05

Research paper (scientific journal), Joint Work, Accepted

Volumetric and timescale analysis of phase transformation in single-crystal silicon during nanoindentation

H. Huang, J. Yan

Applied Physics A 122 ( 607 ) 1 - 11 2016.05

Research paper (scientific journal), Joint Work, Accepted

In situ characterization of formation and growth of high-pressure phases in single-crystal silicon during nanoindentation

H. Huang, J. Yan

Applied Physics A 122 ( 409 ) 1 - 7 2016.03

Research paper (scientific journal), Joint Work, Accepted

Precision slicing of single-crystal silicon using a dicing wire saw

T. Suzuki, T. Otsuki, J. Yan

Journal of the Japan Society for Abrasive Technology 60 ( 2 ) 97-103 2016.02

Research paper (scientific journal), Joint Work, Accepted

Microstructure, mechanical and tribological properties of CrSiC coatings sliding against SiC and Al₂O₃ balls in water

Z. Wu, F. Zhou, K. Chen, Q. Wang, Z. Zhou, J. Yan, L. K. Y. Li

Applied Surface Science 368 129 - 139 2016.02

Research paper (scientific journal), Joint Work, Accepted

Friction and wear properties of CrSiCN coatings with low carbon content as sliding against SiC and steel balls in water

Z. Wu, F. Zhou, K. Chen, Q. Wang, Z. Zhou, J. Yan, L. K. Y. Li

Tribology International 94 176 - 186 2016.01

Research paper (scientific journal), Joint Work, Accepted

Press Molding of a Si-HDPE Hybrid Lens Substrate and Evaluation of Its Infrared Optical Properties

A. R. Abdul Manaf, J. Yan

Precision Engineering 43 429 - 438 2016.01

Research paper (scientific journal), Joint Work, Accepted

Evaluating mechanical properties and crack resistance of CrN, CrTiN, CrAlN and CrTiAlN coatings by nanoindentation and scratch tests

Q. Wang, F. Zhou, J. Yan

Surface and Coatings Technology 285 203 - 213 2016.01

Research paper (scientific journal), Joint Work, Accepted

High-precision drilling of CFRP by ultrasonic vibration-assisted grinding

T. Yamazaki, J. Yan

Journal of the Japan Society for Abrasive Technology 59 ( 12 ) 699-704 2015.12

Research paper (scientific journal), Joint Work, Accepted

Possibility for rapid generation of high-pressure phases in single-crystal silicon by fast nanoindentation

H. Huang, J. Yan

Semiconductor Science and Technology 30 ( 115001 ) 2015.11

Research paper (scientific journal), Joint Work, Accepted

On the surface characteristics of a Zr-based bulk metallic glass processed by microelectrical discharge machining

H. Huang, J. Yan

Applied Surface Science 355 1306 - 1315 2015.11

Research paper (scientific journal), Joint Work, Accepted

Water Repellency Control of Oxygen-Free Copper Surface by Diamond-Cut Micro Grooves

K. Asakura, J. Yan

International Journal of Automation Technology 9 396 - 402 2015.11

Research paper (scientific journal), Joint Work, Accepted

Influence of trimethylsilane flow on the microstructure, mechanical and tribological properties of CrSiCN coatings in water lubrication

Z. Wu, F. Zhou, Q. Wang, Z. Zhou, J. Yan, L. K. Y. Li

Applied Surface Science 355 516 - 530 2015.10

Research paper (scientific journal), Joint Work, Accepted

Comparison of crack resistance between ternary CrSiC and quaternary CrSiCN coatings via nanoindentation

Q. Wang, Z. Wu, F. Zhou, J. Yan

Materials Science and Engineering: A 642 391 - 397 2015.10

Research paper (scientific journal), Joint Work, Accepted

Study on Mechanical Properties of Single-Crystal Silicon Carbide by Nanoindentation

M. Matsumoto, H. Harada, K. Kakimoto, J. Yan

Advanced Materials Research 1136 549 - 554 2015.09

Research paper (scientific journal), Joint Work, Accepted

On the mechanism of secondary pop-out in cyclic nanoindentation of single-crystal silicon

H. Huang, J. Yan

Journal of Materials Research 30 ( 11 ) 1861 - 1868 2015.06

Research paper (scientific journal), Joint Work, Accepted

Sintered diamond as a hybrid EDM and grinding tool for the micromachining of single-crystal SiC

J. Yan, T. H. Tan

CIRP Annals – Manufacturing Technology 64 ( 1 ) 221 - 224 2015.05

Research paper (scientific journal), Joint Work, Accepted

Anisotropy of synthetic diamond in catalytic etching using iron powder

J. Wang, L. Wan, J. Chen, J. Yan

Applied Surface Science 346 388 - 393 2015.05

Research paper (scientific journal), Joint Work, Accepted

Evaluation of crack resistance of CrSiCN coatings as a function of Si concentration via nanoindentation

Q. Wang, Z. Wu, F. Zhou, H. Huang, K. Niitsu, J. Yan

Surface and Coatings Technology 272 239 - 245 2015.04

Research paper (scientific journal), Joint Work, Accepted

Comparison of tribological and electrochemical properties of TiN, CrN, TiAlN and a-C:H coatings in simulated body fluid

Q. Wang, F. Zhou, C. Wang, M. F. Yuen, M. Wang, T. Qian, M. Matsumoto, J. Yan

Materials Chemistry and Physics 156 74 - 81 2015.04

Research paper (scientific journal), Joint Work, Accepted

New insights into phase transformations in single crystal silicon by controlled cyclic nanoindentation

H. Huang, J. Yan

Scripta Materialia 102 35 - 38 2015.03

Research paper (scientific journal), Joint Work, Accepted

Experimental study of crystal anisotropy based on ultra-precision cylindrical turning of single-crystal calcium fluoride

S. Azami, H. Kudo, Y. Mizumoto, T. Tanabe, J. Yan, Y. Kakinuma

Precision Engineering 40 172 - 181 2015.03

Research paper (scientific journal), Joint Work, Accepted

Effect of counterparts on the tribological properties of TiCN coatings with low carbon concentration in water lubrication

Q. Wang, F. Zhou, S. Gao, Z. Zhou, L. K. Y. Li, J. Yan

Wear 328–329 356 - 362 2015.02

Research paper (scientific journal), Joint Work, Accepted

Laser sintering of silicon powder and carbon nanofibers for porous composite thick films

Y. Iwabuchi, J. Yan

Applied Physics Express 8 ( 026501 ) 2015.02

Research paper (scientific journal), Joint Work, Accepted

Influence of carbon concentration on the electrochemical behavior of CrCN coatings in simulated body fluid

Q. Wang, F. Zhou, Z. Zhou, L. K. Y. Li, J. Yan

Surface and Coatings Technology 265 16 - 23 2015.02

Research paper (scientific journal), Joint Work, Accepted

High-precision press sintering for porous silicon-carbon conposite thick films

T. Kidokoro, J. Yan

Journal of the Japan Society for Abrasive Technology 59 ( 1 ) 23-26 2015.01

Research paper (scientific journal), Joint Work, Accepted

Development of polycrystalline Ni–P mold by heat treatment for glass microgroove forming

T. Zhou, J. Yan, Z. Liang, X. Wang, R. Kobayashi, T. Kuriyagawa

Precision Engineering 39 ( 1 ) 25-30 2015.01

Research paper (scientific journal), Joint Work, Accepted

Effects of Element Doping in Ultra-Precision Diamond Turning of Single-Crystal Silicon

Y. Kusunoki, J. Yan

Journal of the Japan Society for Abrasive Technology 58 ( 11 ) 699-704 2014.11

Research paper (scientific journal), Joint Work, Accepted

Ultraprecision micro grooving on brass for surface wettability control

K. Asakura, J. Yan

Advanced Materials Research 1017 489-494 2014.09

Research paper (scientific journal), Joint Work, Accepted

Electrochemical performance of TiCN coatings with low carbon concentration in simulated body fluid

Q. Wang, F. Zhou, Z. Zhou, L.K.Y. Li, J. Yan

Surface and Coatings Technology 253 199 - 204 2014.08

Research paper (scientific journal), Joint Work, Accepted

Micro-electrical discharge machining of polycrystalline diamond using rotary cupronickel electrode

J. Yan, K. Watanabe, T. Aoyama

CIRP Annals – Manufacturing Technology 63 ( 1 ) 209 - 212 2014.07

Research paper (scientific journal), Joint Work, Accepted

Nanoindentation of polysilicon and single crystal silicon: Molecular dynamics simulation and experimental validation

S. Goel, N. Faisal, X. Luo,　J. Yan, A. Agrawal

Journal of Physics D: Applied Physics 47 275304, 1 - 14 2014.06

Research paper (scientific journal), Joint Work, Accepted

Incipient plasticity in 4H-SiC during quasistatic nanoindentation

S. Goel, J. Yan, X. Luo, A. Agrawal

Journal of the Mechanical Behavior of Biomedical Materials 34 330 - 337 2014.06

Research paper (scientific journal), Joint Work, Accepted

Fabrication of Deep Micro Holes in Reaction-Bonded SiC by Ultrasonic Cavitation Assisted Micro EDM

P. J. Liew, J. Yan, T. Kuriyagawa

International Journal of Machine Tools and Manufacture 76 13 - 20 2014.01

Research paper (scientific journal), Joint Work, Accepted

Control of TIG Arc Behavior by YAG Laser and Development of Laser Weaving Method

Y. Murata, A. Itoh, J. Yan, Y. Suga

Journal of Smart Processing 2 ( 6 ) 333 - 339 2013.11

Research paper (scientific journal), Joint Work, Accepted

Fabrication of Microstructures on RB-SiC by Ultrasonic Cavitation Assisted Micro-Electrical Discharge Machining

P. J. Liew, K. Shimada, M. Mizutani, J. Yan, T. Kuriyagawa

International Journal of Automation Technology 7 ( 6 ) 621 - 629 2013.10

Research paper (scientific journal), Joint Work, Accepted

Experimental Investigation on Material Migration Phenomena in Micro EDM of Reaction-Bonded Silicon Carbide

P. J. Liew, J. Yan, T. Kuriyagawa

Applied Surface Science 276 731-743 2013.08

Research paper (scientific journal), Joint Work, Accepted

Fabrication of Thin-Film Fresnel Optics by Combining Diamond Turning and Photolithographic Processes

J. Yan, K. Watanabe, Y. Nakagawa

International Journal of Automation Technology 7 ( 4 ) 385-390 2013.07

Research paper (scientific journal), Joint Work, Accepted

Carbon nanofiber assisted micro electro discharge machining of reaction-bonded silicon carbide

P. J. Liew, J. Yan, T. Kuriyagawa

Journal of Materials Processing Technology 213 ( 7 ) 1076-1087 2013.07

Research paper (scientific journal), Joint Work, Accepted

Laser recovery of machining damage under curved silicon surface

J. Yan, F. Kobayashi

CIRP Annals – Manufacturing Technology 62 ( 1 ) 199-202 2013.04

Research paper (scientific journal), Joint Work, Accepted

Micro-cutting characteristics of EDM fabricated high-precision polycrystalline diamond tools

Z. Zhang, H. Peng, J. Yan

International Journal of Machine Tools & Manufacture 65 99-106 2013.02

Research paper (scientific journal), Joint Work, Accepted

Investigation of particle impact phenomena in powder jet deposition process

C. Nishikawa, K. Mizutani, T. Zhou, J. Yan, T. Kuriyagawa

Key Engineering Materials 523-524 184-189 2012.11

Research paper (scientific journal), Joint Work, Accepted

Statistical approach for calculating ground surface roughness of ultrasonic-assisted grinding

K. Shimada, T. Zhou, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 56 ( 11 ) 752-757 2012.11

Research paper (scientific journal), Joint Work, Accepted

Statistical approach optimizing slant feed grinding

K. Shimada, P. J. Liew, T. Zhou, J. Yan, and T. Kuriyagawa

Journal of Advanced Mechanical Design, Systems, and Manufacturing 6 ( 6 ) 898-907 2012.11

Research paper (scientific journal), Joint Work, Accepted

Effect of Different Dielectric Fluids on Micro EDM of Low Conductivity Ceramic Material RB-SiC

P. J. Liew, J. Yan, T. Masaki, T. Kuriyagawa

Advanced Materials Research 565 529-534 2012.09

Research paper (scientific journal), Joint Work, Accepted

Crystallographic effect on subsurface damage formation in silicon microcutting

J. Yan, T. Asami, H. Harada, T. Kuriyagawa

CIRP Annals – Manufacturing Technology 61 ( 1 ) 131-134 2012.08

Research paper (scientific journal), Joint Work, Accepted

Fabrication of polycrystalline diamond tools by micro electrodischarge machining

Z. Zhang, H. Peng, J. Yan, T. Kuriyagawa

Advanced Materials Research 497 225-229 2012.04

Research paper (scientific journal), Joint Work, Accepted

Size effects on transferability and mold change of glass molding press for microgrooves

T. Zhou, J. Yan, T. Kuriyagawa

Advanced Materials Research 497 235-239 2012.04

Research paper (scientific journal), Joint Work, Accepted

Investigation of wheel wear mechanism during grinding optical glasses through statistical analysis of wheel topography

P. Yao, Y. Gong, T. Matsuda, T. Zhou, J. Yan, and T. Kuriyagawa

International Journal of Abrasive Technology 5 ( 1 ) 33-47 2012.03

Research paper (scientific journal), Joint Work, Accepted

Study on the mechanism of power jet machining

C. Nishikawa, K. Mizutani, T. Zhou, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 56 ( 3 ) 179-183 2012.03

Research paper (scientific journal), Joint Work, Accepted

Material removal mechanism of ultrasonic machining

T. Katahira, K. Shimada, T. Zhou, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 56 ( 2 ) 108-111 2012.02

Research paper (scientific journal), Joint Work, Accepted

High Efficiency Precision Surface Grinding of Fused Silica

P. Yao, Y. Gong, S. Yuan, N. Yoshihara, J. Yan, T. Kuriyagawa

Advanced Materials Research 418-420 1132-1136 2012.01

Research paper (scientific journal), Joint Work, Accepted

Manufacturing Structured Surface by Combining Microindentation and Ultraprecision Cutting

J. Yan, A. Horikoshi, T. Kuriyagawa, and Y. Fukushima

CIRP Journal of Manufacturing Science and Technology 5 ( 1 ) 652-655 2012.01

Research paper (scientific journal), Joint Work, Accepted

Development of uniformly dispersed and well-classified diamond abrasive wheel for nano-precision grinding

K. Matsumoto, T. Zhou, J. Yan, H. Matsuura, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 55 ( 11 ) 652-655 2011.11

Research paper (scientific journal), Joint Work, Accepted

Laser-assisted powder jet deposition

N. Yoshihara, R. Hiromatsu, K. Mizutani, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 55 ( 10 ) 606-610 2011.10

Research paper (scientific journal), Joint Work, Accepted

Effect of Nanoparticle Lubrication in Diamond Turning of Reaction-Bonded SiC

J. Yan, Z. Zhang, and T. Kuriyagawa

International Journal of Automation Technology 5 ( 3 ) 307-312 2011.10

Research paper (scientific journal), Joint Work, Accepted

Ultrasonic-Assisted Grinding of Ultra-High Purity SUS 316L

K. Shimada, N. Yoshihara, J. Yan, T. Kuriyagawa, Y. Sueishi, and H. Tezuka

International Journal of Automation Technology 5 ( 3 ) 427-432 2011.10

Research paper (scientific journal), Joint Work, Accepted

Statistical Approach Calculating Ground Surface Roughness of Ultrasonic-assisted Micro-grinding

K. Shimada, T. Zhou, J. Yan, T. Kuriyagawa

Advanced Materials Research 325 600-605 2011.09

Research paper (scientific journal), Joint Work, Accepted

Experimental research on a modular miniaturization nanoindentation device

H. Huang, H. Zhao, J. Mi, J. Yang, S. Wan, Z, Yang, J. Yan, Z. Ma, C. Geng

Review of Scientific Instruments 82 ( 9 ) 095101 (1-6) 2011.09

Research paper (scientific journal), Joint Work, Accepted

Study on tool wear characteristics in diamond turning of reaction-bonded silicon carbide

Z. Zhang, J. Yan, and T. Kuriyagawa

International Journal of Advanced Manufacturing Technology 57 ( 1 ) 117-125 2011.09

Research paper (scientific journal), Joint Work, Accepted

Ultraprecision Mass Fabrication of Aspherical Fresnel Lens by Glass Molding Press

T. Zhou, J. Yan, J. Masuda, T. Kuriyagawa

Advanced Materials Research 325 713-718 2011.08

Research paper (scientific journal), Joint Work, Accepted

Ultraprecision cutting of photoresist/gold composite microstructures

J. Yan

CIRP Annals – Manufacturing Technology 60 ( 1 ) 133-136 2011.08

Research paper (scientific journal), Single Work, Accepted

Thermal Analysis of Laser Irradiation of Fused Silica

P. Yao, Y. Gong, S. Yuan, T. Zhou, J. Yan, T. Kuriyagawa

Advanced Materials Research 314-316 1960-1964 2011.08

Research paper (scientific journal), Joint Work, Accepted

On-Machine Measurement and Statistical Analysis of Wheel Wear After Grinding of Optical Glass

P. Yao, T. Matsuda, T. Zhou, J. Yan, T. Kuriyagawa, Y. Gong

Advanced Materials Research 325 653-658 2011.08

Research paper (scientific journal), Joint Work, Accepted

Investigation on Shape Transferability in Ultraprecision Glass Molding Press for Microgrooves

T. Zhou, J. Yan, J. Masuda, T. Oowada, and T. Kuriyagawa

Precision Engineering 35 ( 2 ) 214-220 2011.06

Research paper (scientific journal), Joint Work, Accepted

Characterization of microparticles and oxide layers generated by laser irradiation of diamond-machined silicon wafers

J. Yan, S. Sakai, H. Isogai, and K. Izunome

Semiconductor Science and Technology 26 ( 2 ) 025006 (1-7) 2011.02

Research paper (scientific journal), Joint Work, Accepted

Thermally-induced atomic diffusion at the interface between release agent coating and mould substrate in a glass moulding press

J. Masuda, J. Yan, T. Zhou, T. Kuriyagawa, and Y. Fukase

Journal of Physics D: Applied Physics 44 ( 21 ) 215302 (1-12) 2011.02

Research paper (scientific journal), Joint Work, Accepted

Subsurface damage of single crystalline silicon carbide in nanoindentation tests

J. Yan, X. Gai and H. Harada

Journal of Nanoscience and Nanotechnology 10 ( 11 ) 7808-7811 2010.11

Research paper (scientific journal), Joint Work, Accepted

Tool-Swinging Cutting of Binderless Tungsten Carbide

Z. Zhang, J. Yan, T. Kuriyagawa

Advanced Materials Research 139-141 727-730 2010.10

Research paper (scientific journal), Joint Work, Accepted

Fabricating micro grooves with varied cross-sections by electro discharge machining

J. Yan, T. Kaneko, K. Uchida, N. Yoshihara, T. Kuriyagawa

International Journal of Advanced Manufacturing Technology 50 ( 9-12 ) 991-1002 2010.10

Research paper (scientific journal), Joint Work, Accepted

Development of a high-frequency pulse laser irradiation system for repairing silicon wafers damaged by abrasive machining processes

J. Yan, S. Muto, and T. Kuriyagawa

International Journal of Abrasive Technology 3 ( 3 ) 175-189 2010.09

Research paper (scientific journal), Joint Work, Accepted

Fabricating micro-structured surface by using single-crystalline diamond endmill

J. Yan, Z. Zhang, and T. Kuriyagawa

International Journal of Advanced Manufacturing Technology 51 ( 9 ) 957-964 2010.09

Research paper (scientific journal), Joint Work, Accepted

Ductile and Brittle Mode Grinding of Fused Silica

P. Yao, N. Yoshihara, N. Hitomi, J. Yan, T. Kuriyagawa

Key Engineering Materials 447-448 21-25 2010.08

Research paper (scientific journal), Joint Work, Accepted

Tool wear control in diamond turning of high-strength mold materials by means of tool swinging

J. Yan, Z. Zhang, T. Kuriyagawa

CIRP Annals – Manufacturing Technology 59 ( 1 ) 109-112 2010.08

Research paper (scientific journal), Joint Work, Accepted

Repairing Damage on Ground Fused Silica by CO₂ Laser Irradiation

P. Yao, T. Abe, N. Yoshihara, T. Zhou, J. Yan, T. Kuriyagawa

Advanced Materials Research 126-128 401-406 2010.08

Research paper (scientific journal), Joint Work, Accepted

Laser Assist Powder Jet Deposition

N. Yoshihara, R. Hiromatsu, K. Mizutani, J. Yan, T. Kuriyagawa

Advanced Materials Research 126-128 58-63 2010.08

Research paper (scientific journal), Joint Work, Accepted

Comparing Microgroove Array Forming with Micropyramid Array Forming in the Glass Molding Press

T. Zhou, J. Yan, T. Kuriyagawa

Key Engineering Materials 447-448 361-365 2010.08

Research paper (scientific journal), Joint Work, Accepted

Effect of Grain Cutting Direction for Ground Surface Roughness: Study on Nonaxisymmetric Aspherical Grinding

N. Yoshihara, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Precision Engineering 76 ( 7 ) 781-785 2010.07

Research paper (scientific journal), Joint Work, Accepted

Restoration of the retention force of a small-diameter thermoplastic resin-bonded wheel by laser treatment

H. Matsuura, Y. Kunieda, N. Yoshihara, M. Tanabe, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 54 ( 5 ) 282-287 2010.05

Research paper (scientific journal), Joint Work, Accepted

Study on Nonisothermal Glass Molding Press for Aspherical Lens

T. Zhou, J. Yan, N. Yoshihara, and T. Kuriyagawa

Journal of Advanced Mechanical Design, Systems, and Manufacturing 4 ( 5 ) 804-815 2010.05

Research paper (scientific journal), Joint Work, Accepted

Deformation in mono-crystalline silicon caused by high speed single-point micro-cutting

A. Q. Biddut, J. Yan, L. C. Zhang, T. Ohta, B. Shaun, T. Kuriyagawa

Key Engineering Materials 407-408 347-350 2010.04

Research paper (scientific journal), Joint Work, Accepted

Restoration of the retention force of a small-diameter thermoplastic resin-bonded wheel by laser treatment

H. Matsuura, Y. Kunieda, N. Yoshihara, M. Tanabe, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Precision Engineering 176 ( 3 ) 327-332 2010.03

Research paper (scientific journal), Joint Work, Accepted

Ultrasonic-assisted micro-grinding using electroplated diamond wheels (2nd Report: Effect of ultrasonic vibration on workpiece removal in grinding with wheel end)

K. Shimada, T. Tateishi, N. Yoshihara, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 54 ( 1 ) 37-40 2010.01

Research paper (scientific journal), Joint Work, Accepted

Performance of the thermoplastic resin-bonded diamond wheel

H. Matsuura, S. Kodama, Y. Kunieda, N. Yoshihara, M. Tanabe, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 53 ( 12 ) 756-761 2009.12

Research paper (scientific journal), Joint Work, Accepted

Development of the thermoplastic-resin bonded diamond wheel and the control of protrusion height by irradiation with laser light using a flashlamp-pumped pulse laser

H. Matsuura, S. Kodama, Y. Kunieda, N. Yoshihara, M. Tanabe, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 53 ( 11 ) 679-683 2009.11

Research paper (scientific journal), Joint Work, Accepted

Fundamental investigation on subsurface damage in single crystalline silicon caused by diamond machining

J. Yan, T. Asami, H. Harada, and T. Kuriyagawa

Precision Engineering 33 ( 4 ) 378-386 2009.11

Research paper (scientific journal), Joint Work, Accepted

Recovery of microstructure and surface topography of grinding-damaged silicon wafers by nanosecond-pulsed laser irradiation

J. Yan, S. Sakai, H. Isogai, and K. Izunome

Semiconductor Science and Technology 24 ( 10 ) 105018 (1-6) 2009.10

Research paper (scientific journal), Joint Work, Accepted

Investigation on the viscoelasticity of optical glass in ultraprecision lens molding process

T. Zhou, J. Yan, J. Masuda, and T. Kuriyagawa

Journal of Materials Processing Technology 209 ( 9 ) 4484-4489 2009.10

Research paper (scientific journal), Joint Work, Accepted

Precision machining of microstructures on electroless-plated NiP surface for molding glass components

J. Yan, T. Oowada, T. Zhou, and T. Kuriyagawa

Journal of Materials Processing Technology 209 ( 10 ) 4802-4808 2009.10

Research paper (scientific journal), Joint Work, Accepted

Effect of Electrorheological Fluid Assistance for Micro Ultrasonic Machining

T. Tateishi, K. Shimada, N. Yoshihara, J. Yan, T. Kuriyagawa

Advanced Materials Research 76-78 148-152 2009.09

Research paper (scientific journal), Joint Work, Accepted

Processing Grinding-damaged Silicon Wafers by Nano-second Laser Irradiation

J. Yan, S. Muto, T. Kuriyagawa

Advanced Materials Research 76-78 451-456 2009.09

Research paper (scientific journal), Joint Work, Accepted

Effects of tool edge radius on ductile machining of silicon: an investigation by FEM

J. Yan, H. Zhao, and T. Kuriyagawa

Semiconductor Science and Technology 24 ( 7 ) 075018 (1-11) 2009.07

Research paper (scientific journal), Joint Work, Accepted

Modeling high-temperature glass molding process by coupling heat transfer and viscous deformation analysis

J. Yan, T. Zhou, J. Masuda, and T. Kuriyagawa

Precision Engineering 33 ( 2 ) 150-159 2009.06

Research paper (scientific journal), Joint Work, Accepted

Mechanism for material removal in diamond turning of reaction-bonded silicon carbide

J. Yan, Z. Zhang, and T. Kuriyagawa

International Journal of Machine Tools & Manufacture 49 ( 5 ) 366-374 2009.05

Research paper (scientific journal), Joint Work, Accepted

Microstructural and Topographical Changes of Ni-P Plated Molds in Glass Lens Pressing

J. Masuda, J. Yan, T. Tashiro, Y. Fukase, T. Zhou and T. Kuriyagawa

International Journal of Surface Science and Engineering 3 ( 1-2 ) 86-102 2009.03

Research paper (scientific journal), Joint Work, Accepted

Study on electrorheological fluid-assisted micro ultrasonic machining

T. Tateishi, N. Yoshihara, J. Yan, and T. Kuriyagawa

International Journal of Abrasive Technology 2 ( 1 ) 70-82 2009.03

Research paper (scientific journal), Joint Work, Accepted

Finite element modeling of high-pressure deformation and phase transformation of silicon beneath a sharp indenter

T. Kiriyama, H. Harada, and J. Yan

Semiconductor Science and Technology 24 ( 2 ) 025014 (1-12) 2009.02

Research paper (scientific journal), Joint Work, Accepted

Fabricating Nano Ribbons and Nano Fibers of Semiconductor Materials by Diamond Turning

J. Yan, X. Gai and T. Kuriyagawa

Journal of Nanoscience and Nanotechnology 9 ( 2 ) 1423-1427 2009.02

Research paper (scientific journal), Joint Work, Accepted

Shape transferability and microscopic deformation of molding dies in aspherical glass lens molding press

J. Yan, T. Zhou, N. Yoshihara, and T. Kuriyagawa

Journal of Manufacturing Technology Research 1 ( 1-2 ) 85-102 2009.02

Research paper (scientific journal), Joint Work, Accepted

Fabrication of micro end mills by wire EDM and some micro cutting tests

J. Yan, K. Uchida, N. Yoshihara, and T. Kuriyagawa

Journal of Micromechanics and Microengineering 19 ( 2 ) 025004 (1-9) 2009.02

Research paper (scientific journal), Joint Work, Accepted

Ultrasonic-assisted micro-grinding using electroplated diamond wheels

K. Shimada, T. Tateishi, N. Yoshihara, J. Yan, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 53 ( 1 ) 45-48 2009.01

Research paper (scientific journal), Joint Work, Accepted

Control of the behavior of abrasive grains by the effect of electrorheological fluid assistance - Study on electrorheological fluid-assisted micro ultrasonic machining

T. Tateishi, K. Shimada, N. Yoshihara, J. Yan, T. Kuriyagawa

Advanced Materials Research 69-70 148-152 2008.11

Research paper (scientific journal), Joint Work, Accepted

High-efficiency ultraprecision machining characteristics of single-crystal germanium

T. Ota, J. Yan, S. Kodera, S. Yajima, Y. Takahashi, N. Horikawa, and T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 52 ( 11 ) 651-656 2008.11

Research paper (scientific journal), Joint Work, Accepted

Surface and subsurface damages in nanoindentation tests of compound semiconductor InP

J. Yan, J. Tamaki, H. Zhao and T. Kuriyagawa

Journal of Micromechanics and Microengineering 18 ( 10 ) 105018 (1-10) 2008.10

Research paper (scientific journal), Joint Work, Accepted

Experimental Analysis of Elastic and Plastic Behavior in Ductile-Regime Machining of Glass Quartz Utilizing a Diamond Tool

J. Tamaki, A. Kubo and J. Yan

Key Engineering Materials 389-390 30-35 2008.09

Research paper (scientific journal), Joint Work, Accepted

Recovery of Subsurface Structures of Machining-Damaged Single Crystalline Silicon by Nd:YAG Laser Irradiation

J. Yan, T. Asami, T. Kuriyagawa

Key Engineering Materials 389-390 469-474 2008.09

Research paper (scientific journal), Joint Work, Accepted

Design of Double Nozzle Type Powder Jet Device Optimized for PJD

T. Shibuya, M. S. Sepasy, K. Mizutani, N. Yoshihara, J. Yan, T. Kuriyagawa

Key Engineering Materials 389-390 398-403 2008.09

Research paper (scientific journal), Joint Work, Accepted

Fabrication of high-aspect ratio micro holes on hard brittle materials-Study on electrorheological fluid-assisted micro ultrasonic machining

T. Tateishi, N. Yoshihara, J. Yan, T. Kuriyagawa

Key Engineering Materials 389-390 264-270 2008.09

Research paper (scientific journal), Joint Work, Accepted

Machinability investigation of reaction-bonded silicon carbide by single-point diamond turning

Z. Zhang, J. Yan, T. Kuriyagawa

Key Engineering Materials 389-390 151-156 2008.09

Research paper (scientific journal), Joint Work, Accepted

Coolant effects on tool wear in machining single-crystal silicon with diamond tools

T. Ohta, J. Yan, S. Kodera, S. Yajima, N. Horikawa, Y. Takahashi and T. Kuriyagawa

Key Engineering Materials 389-390 144-150 2008.09

Research paper (scientific journal), Joint Work, Accepted

Coolant effects on tool wear in machining single-crystal silicon with diamond tools

Y. Nagaike, T. Kuriyagawa, W. Gao, J. Yan, and N. Yoshihara

Key Engineering Materials 389-390 102-107 2008.09

Research paper (scientific journal), Joint Work, Accepted

Control of nano-topography on an axisymmetric ground surface

N. Yoshihara, J. Yan, and T. Kuriyagawa

Key Engineering Materials 389-390 96-101 2008.09

Research paper (scientific journal), Joint Work, Accepted

Nondestructive measurement of the machining-induced amorphous layers in single-crystal silicon by laser micro-Raman spectroscopy

J. Yan, T. Asami, and T. Kuriyagawa

Precision Engineering 32 ( 3 ) 186-195 2008.09

Research paper (scientific journal), Joint Work, Accepted

Application of the NiP-plated steel molds to glass lens molding

J. Masuda, J. Yan, T. Kuriyagawa

Journal of the Japan Society for Abrasive Technology 52 ( 8 ) 444-448 2008.08

Research paper (scientific journal), Joint Work, Accepted

Interlayer growth and fracture at joint interface of pure aluminium / pure nickel friction welded joint

A. Fuji, T. Nagano, Y. C. Kim, and J. Yan

Welding International 22 ( 3 ) 137-147 2008.03

Research paper (scientific journal), Joint Work, Accepted

Nano precision on-machine profiling of curved diamond cutting tools using a white-light interferometer

J. Yan, H. Baba, Y. Kunieda, N. Yoshihara, and T. Kuriyagawa

International Journal of Surface Science and Engineering 1 ( 4 ) 441-455 2007.12

Research paper (scientific journal), Joint Work, Accepted

Study on shaping spherical Poly Crystalline Diamond tool by Micro-electro-Discharge Machining and micro-grinding with the tool

T. Masaki, T. Kuriyagawa, J. Yan, and N. Yoshihara

International Journal of Surface Science and Engineering 1 ( 4 ) 344-359 2007.12

Research paper (scientific journal), Joint Work, Accepted

High-efficiency machining of single-crystal germanium using large-radius diamond tools

T. Ohta, J. Yan, S. Yajima, Y. Takahashi, N. Horikawa, and T. Kuriyagawa

International Journal of Surface Science and Engineering 1 ( 4 ) 374-392 2007.12

Research paper (scientific journal), Joint Work, Accepted

Response of machining-damaged single-crystalline silicon wafers to nanosecond pulsed laser irradiation

J. Yan, T. Asami and T. Kuriyagawa

Semiconductor Science and Technology 22 ( 4 ) 392-395 2007.04

Research paper (scientific journal), Joint Work, Accepted

Electrolytic conditioning of resin-metal-bonded diamond grinding wheels

N. Yoshihara, M. Ma, J. Yan, and T. Kuriyagawa

International Journal of Abrasive Technology 1 ( 1 ) 136-142 2007.01

Research paper (scientific journal), Joint Work, Accepted

Grain exfoliation and control thereof in ultra-precision plane honing of AlN substrates

S. Suzuki, T. Kuriyagawa, J. Yan, and N. Yoshihara

International Journal of Machining and Machinability of Materials 2 ( 1 ) 37-49 2007.01

Research paper (scientific journal), Joint Work, Accepted

Prediction of subsurface damage depth of ground brittle materials by surface profiling

T. Ohta, J. Yan, T. Kuriyagawa, S. Kodera, and T. Nakasuji

International Journal of Machining and Machinability of Materials 2 ( 1 ) 108-124 2007.01

Research paper (scientific journal), Joint Work, Accepted

Development of Laser Dresser for Resin Bonded Diamond Wheel

H. Matsuura, K. Hane, Y. Kunieda, N. Yoshihara, J. Yan, T. Kuriyagawa

Key Engineering Materials 329 169-174 2006.09

Research paper (scientific journal), Joint Work, Accepted

Development of a Rubber-Bonded Grinding Wheel- Studies on Aspherical Grinding

N. Yoshihara, J. Yan, T. Kuriyagawa

Key Engineering Materials 329 465-470 2006.09

Research paper (scientific journal), Joint Work, Accepted

Development of 3R Diamond Wheel by Thermoplastic Resin Bond

H. Matsuura, Y. Kunieda, N. Yoshihara, J. Yan, T. Kuriyagawa

Key Engineering Materials 329 459-464 2006.09

Research paper (scientific journal), Joint Work, Accepted

Numerical Simulation and Prediction of Surface Heterogeneity in Diamond Turning of Single-Crystalline Germanium

J. Yan, Y. Fan, N. Yoshihara, T. Kuriyagawa

Key Engineering Materials 329 397-402 2006.09

Research paper (scientific journal), Joint Work, Accepted

High-Efficiency Mirror Grinding of AlN by Ultra-Precision Plane Horning

S. Suzuki, N. Yoshihara, J. Yan, T. Kuriyagawa

Key Engineering Materials 329 291-296 2006.09

Research paper (scientific journal), Joint Work, Accepted

Development of a Resin-Coated Micro Polishing Tool by Plasma CVD Method - Electrorheological fluid-assisted polishing of Tungsten carbide micro aspherical molding dies

T. Kaku, N. Yoshihara, J. Yan, T. Kuriyagawa, K. Abiko, Y. Mikami and M. Noguchi

Key Engineering Materials 329 213-218 2006.09

Research paper (scientific journal), Joint Work, Accepted

Development of a New Laser Conditioning Method for Ultra-Fine Grit Diamond Wheels

Y. Kunieda, H. Matsuura, S. Kodama, N. Yoshihara, J. Yan, T. Kuriyagawa

Key Engineering Materials 329 175-180 2006.09

Research paper (scientific journal), Joint Work, Accepted

Load effects on the phase transformation of single-crystal silicon during nanoindentation tests

J. Yan, H. Takahashi, X. Gai, H. Harada, J. Tamaki and T. Kuriyagawa

Materials Science and Engineering A 423 ( 1-2 ) 19-23 2006.02

Research paper (scientific journal), Joint Work, Accepted

Ultraprecision Machining Characteristics of Poly-crystalline Germanium

J. Yan, Y. Takahashi, J. Tamaki, A. Kubo, T. Kuriyagawa and Y. Sato

JSME International Journal, Series C 49 ( 1 ) 63-69 2006.01

Research paper (scientific journal), Joint Work, Accepted

Transmission electron microscopic observation of nanoindentations made on ductile-machined silicon wafers

J. Yan, H. Takahashi, J. Tamaki, X. Gai, and T. Kuriyagawa

Applied Physics Letters 87 ( 11 ) 211901 (1-3) 2005.11

Research paper (scientific journal), Joint Work, Accepted

Micro grooving on single-crystal germanium for infrared Fresnel lenses

J. Yan, K. Maekawa, J. Tamaki and T. Kuriyagawa

Journal of Micromechanics and Microengineering 15 ( 10 ) 1925-1931 2005.10

Research paper (scientific journal), Joint Work, Accepted

Effect of Cutting Edge Truncation on Ground Surface Morphology of Hard and Brittle Materials for Optical Devices

X. Kang, J. Tamaki, A. Kubo, J. Yan, and T. Iyama

Key Engineering Materials 291-292 139-144 2005.09

Research paper (scientific journal), Joint Work, Accepted

Effect of cutting edge shape of diamond abrasive grain on ductile mode grinding of optical glass -Measurement of critical depth of cut by means of single grit diamond cutting-

J. Tamaki, G. Sato, K. Maekawa, J. Yan, A. Kubo

Journal of the Japan Society of Grinding Engineers 49 ( 6 ) 335-340 2005.06

Research paper (scientific journal), Joint Work, Accepted

Nanoindentation tests on diamond-machined silicon wafers

J. Yan, H. Takahashi, J. Tamaki, X. Gai, H. Harada, and J. Patten

Applied Physics Letters 85 ( 5 ) 181913 (1-3) 2005.05

Research paper (scientific journal), Joint Work, Accepted

Fabrication of large-curvature optical elements by ultraprecision cutting under 3-axis numerical control

J. Yan, T. Sasaki, J. Tamaki, A. Kubo

Journal of the Japan Society for Abrasive Technology 49 ( 4 ) 205-208 2005.04

Research paper (scientific journal), Joint Work, Accepted

Single-Point Diamond Turning of CaF2 for Nanometric Surface

J. Yan, J. Tamaki, K. Syoji, and T. Kuriyagawa

International Journal of Advanced Manufacturing Technology 24 ( 9-10 ) 640-646 2004.09

Research paper (scientific journal), Joint Work, Accepted

Laser micro-Raman spectroscopy of single-point diamond machined silicon substrates

J. Yan

Journal of Applied Physics 95 ( 4 ) 2094-2101 2004.04

Research paper (scientific journal), Single Work, Accepted

Experimental Study on the Ultraprecision Ductile Machinability of Single-Crystal Germanium

J. Yan, K. Maekawa, J. Tamaki and A. Kubo

JSME International Journal, Series C 47 ( 1 ) 29-36 2004.01

Research paper (scientific journal), Joint Work, Accepted

Crystallographic effects in micro/nanomachining of single-crystal calcium fluoride

J. Yan, K. Syoji and J. Tamaki

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures 22 ( 1 ) 46-51 2004.01

Research paper (scientific journal), Joint Work, Accepted

Improvement of the Crystal Orientation and Surface Roughness of Ru Thin Films by Introducing Oxygen during Sputtering

Y. Abe, S. Shinkai, K. Sasaki, J. Yan, and K. Maekawa

Japanese Journal of Applied Physics 43 ( 1 ) 277-280 2004.01

Research paper (scientific journal), Joint Work, Accepted

Ductile Regime Machining of Single-Crystal CaF2 for Aspherical Lenses

J. Yan, J. Tamaki, K. Syoji, T. Kuriyagawa

Key Engineering Materials 257-258 95-100 2003.11

Research paper (scientific journal), Joint Work, Accepted

Effect of Cutting-Edge Shape on Ductile Regime Grinding of Optical Glass in Single-Grit Diamond Grinding

J. Tamaki, T. Mahmoud, J. Yan, G. Sato, T. Iyama

Key Engineering Materials 257-258 89-94 2003.11

Research paper (scientific journal), Joint Work, Accepted

Chip Formation Behaviour in Ultra-Precision Cutting of Electroless Nickel Plated Mold Substrates

J. Yan, T. Sasaki, J. Tamaki, A. Kubo, T. Sugino

Key Engineering Materials 257-258 3-8 2003.11

Research paper (scientific journal), Joint Work, Accepted

Measurement of three-dimensional shape of diamond abrasive grain utilizing a scanning laser microscope

T. Mahamoud, J. Tamaki, J. Yan, S. Suzuki

Journal of the Japan Society for Abrasive Technology 47 ( 6 ) 314-319 2003.06

Research paper (scientific journal), Joint Work, Accepted

Some observations on the wear of diamond tools in ultra-precision cutting of single-crystal silicon

J. Yan, K. Syoji and J. Tamaki

Wear 255 ( 712 ) 1380-1387 2003.06

Research paper (scientific journal), Joint Work, Accepted

Development of a Novel Ductile-Machining System for Fabricating Axisymmetrical Aspherical Surfaces on Brittle Materials

J. Yan, J. Tamaki, K. Syoji and T. Kuriyagawa

Key Engineering Materials 238-239 43-48 2002.11

Research paper (scientific journal), Joint Work, Accepted

Electrocontact Discharge Dressing of a Resin-Bonded CBN Grinding Wheel and its Grinding Performance

J. Tamaki, A. Kubo, J. Yan, and K. Narita

Key Engineering Materials 238-239 327-332 2002.11

Research paper (scientific journal), Joint Work, Accepted

Development of a Polishing Disc Containing Granulated Fine Abrasives

H. Nakamura, J. Yan, K. Syoji and Y. Wakamatsu

Key Engineering Materials 238-239 257-262 2002.11

Research paper (scientific journal), Joint Work, Accepted

Three-Dimensional Shape Modeling of Diamond Abrasive Grains Measured by a Scanning Laser Microscope

T. Mahmoud, J. Tamaki and J. Yan

Key Engineering Materials 238-239 131-136 2002.11

Research paper (scientific journal), Joint Work, Accepted

Precision truing of a metal-bonded diamond grinding wheel by means of an envelope generation method

J. Xie, A. Kubo, J. Tamaki, J. Yan

Journal of the Japan Society for Abrasive Technology 46 ( 10 ) 521-526 2002.10

Research paper (scientific journal), Joint Work, Accepted

Electro-contact discharge dressing of a resin-bonded CBN grinding wheel using a low open-circuit voltage

A. Kubo, J. Tamaki, T. Sugino, J. Yan, K. Narita

Journal of the Japan Society for Abrasive Technology 46 ( 7 ) 348-353 2002.07

Research paper (scientific journal), Joint Work, Accepted

Fabrication of Large-Diameter Single-Crystal Silicon Aspheric Lens by Straight-Line Enveloping Diamond-Turning Method

J. Yan, K. Syoji, and T. Kuriyagawa

Journal of the Japan Society for Precision Engineering 68 ( 4 ) 561-565 2002.04

Research paper (scientific journal), Joint Work, Accepted

Ductile Regime Turning at Large Tool Feed

J. Yan, K. Syoji, T. Kuriyagawa and H. Suzuki

Journal of Materials Processing Technology 121 ( 2-3 ) 363-372 2002.02

Research paper (scientific journal), Joint Work, Accepted

Effect of Tool Wear on Diamond Cutting of Single Crystal Silicon

J. Yan, K. Syoji, and T. Kuriyagawa

Transactions of the Japan Society of Mechanical Engineers, Part C 67 ( 664 ) 3999-4004 2001.04

Research paper (scientific journal), Joint Work, Accepted

On the Ductile Machining of Silicon for Micro Electro-mechanical Systems (MEMS), Opto-electronic and Optical Applications

J. Yan, M. Yoshino, T. Kuriagawa, T. Shirakashi, K. Syoji and R. Komanduri

Materials Science and Engineering A 297 ( 1-2 ) 230-234 2001.02

Research paper (scientific journal), Joint Work, Accepted

Ductile-Brittle Transition at Large Negative Tool Rake Angles

J. Yan, K. Syoji, and T. Kuriyagawa

Journal of the Japan Society for Precision Engineering 66 ( 7 ) 1130-1134 2000.07

Research paper (scientific journal), Joint Work, Accepted

Chip Morphology of Ultra-Precision Diamond Turning of Single Crystal Silicon

J. Yan, K. Syoji, and T. Kuriyagawa

Journal of the Japan Society for Precision Engineering 65 ( 7 ) 1008-1012 1999.07

Research paper (scientific journal), Joint Work, Accepted

Study on Ultra-Precision Grinding of Micro Aspherical Surface (3rd Report): Micronizing of Aspherical Surface in Inclined Rotational Grinding

H. Suzuki, T. Kuriyagawa, T. Kuriyagawa, K. Tanaka, J. Yan, N. Wajima, K. Tanaka, and I. Miyoshi

Journal of the Japan Society for Precision Engineering 64 ( 9 ) 1350 - 1354 1998.10

Research paper (scientific journal), Joint Work, Accepted

Ductile Regime Turning of Single Crystal Silicon with a Straight-Nosed Diamond Tool

J. Yan, T. Kuriyagawa, T. Kuriyagawa, H. Suzuki

Journal of the Japan Society for Precision Engineering 64 ( 9 ) 1345 - 1349 1998.09

Research paper (scientific journal), Joint Work, Accepted

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