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Papers - Yan, Jiwang

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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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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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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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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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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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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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