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Influence of processing parameters on the microstructure and tensile property of 85 W-15Ni produced by laser direct deposition
摘要： The plate-like shape 85W-15Ni parts were produced by laser direct deposition technology with different processing parameters (laser power and scanning speed). The influence of processing parameters and their corresponding laser energy density on the microstructural characterization, phase composition and tensile property of 85W-15Ni samples was investigated. The results show that the relative density of samples increased with the laser energy density and the densification trend started to slow as the laser energy density reached 380-400 J/mm3, though the highest density value was obtained with laser energy of 425 J/mm3. With the increase of laser energy density, more disorder and fine W dendrites existed at the bonding region between deposition layers and more W-W grain boundaries formed at the central region of the layer. The 85W-15Ni samples produced with different processing parameters consisted of W and γ-Ni phase. To improve the tensile property, it is necessary to increase the laser energy density to obtain denser structure and reduce the residual pores or gaps. However, the excessive laser energy density resulted in the formation of more W-W grain boundaries that were detrimental to the tensile property. The best tensile properties were obtained at the laser energy density of 395 J/mm3.
关键词： 85W-15Ni,Laser direct deposition,Tensile property,Laser energy density,microstructural characterization
更新于2025-11-28 14:24:20
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Molecular dynamics simulation of coalescence kinetics and neck growth in laser additive manufacturing of aluminum alloy nanoparticles
摘要： Laser additive manufacturing emerged as an advanced manufacturing process to fabricate components in a layered fashion by fusing the powder particles. This process is multifaceted and pivotal to understand the underlying physics of the coalescence of powder particles during the process, which impacts the structural and mechanical properties of the build component. In this study, a classical molecular dynamics (MD) model is developed for the coalescence of pre-alloyed aluminum alloy (AlSi10Mg) particles during the laser additive manufacturing process. The model is employed to investigate the neck growth and coalescence kinetics of different pairs of particle size with changing the laser energy density from 7 to 17 J/mm2. The simulation results reveal that the unevenly sized particles undergo complete coalescence as compared with even-sized particles, and the neck growth rate of AlSi10Mg particles increases with an increase in laser energy density. Based on the present investigation, it is established that the coalescence kinetics of the AlSi10Mg nanoparticles are governed by the surface and volume diffusion and the surface energy reduction during the joining of particles. This analysis will act as a guideline to design process parameters and quality control for the printing of new components.
关键词： Molecular dynamics,Laser additive manufacturing,Coalescence,Laser energy density,Powder bed fusion
更新于2025-09-23 15:21:01
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Influence of Laser Energy Density on Acquisition and Wear Resistance of Bionic Semisolid Unit of 40Cr Steel
摘要： 40Cr steel is one of the most common materials for manufacturing brake camshaft of trailer. The brake camshaft is subjected to extreme wear during its service life. In order to enhance wear resistance, medium frequency induction hardening (MFIH) treatment is usually conducted on the surface of brake camshaft. However, conventional MFIH technique requires heating of the entire surface, which has the drawbacks of more power consumption, high production cost and easy deformation. Therefore, inspired by the bionic theory, a process named as ‘‘laser bionic semisolid treatment’’ method accompanied by favorable surface roughness and minimum distortion has been proposed herein as an alternative to MFIH method. By this means, bionic units with different surface roughness, sizes microstructure and hardness were manufactured on the surface of 40Cr steel. Then, the wear resistance of 40Cr steel with various laser energy densities was experimentally investigated. The results demonstrated that when the laser energy density was 18:00t3 (cid:2)3 J/ mm2, the bionic semisolid unit was obtained with the arithmetic mean surface roughness Ra of 1046.81 nm. Moreover, in the wear resistance of 40Cr steel due to the microstructure and higher hardness compared with the untreated sample, and its weight loss ratio was decreased by 71.90%. The mechanism of wear resistance enhancement was also discussed.
关键词： bionic semisolid unit,40Cr steel,wear resistance,laser energy density,surface roughness
更新于2025-09-23 15:21:01
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Laser energy density dependence of performance in additive/subtractive hybrid manufacturing of 316L stainless steel
摘要： An enormous amount of research effort goes into the manufacturing process for additive manufacturing (AM) or subtractive manufacturing (SM) process for property microstructure. Moreover, additive/subtractive hybrid manufacturing (ASHM), which combines additive and subtractive processes in a single machine, has provided an important opportunity to increase the high percentage of stock utilization and produce complex functional components. However, the system comprehensive investigation and the study of ASHM-manufactured parts by various process parameters have rarely been reported. The present paper depicted the effect of laser energy density (ψ) on the phase change, density, microstructure, Vickers hardness, and tensile testing within the ASHM specimens. It was observed that the highest Vickers microhardness, the largest tensile strength, and the attendant ductility were gained at ψ =222 J/mm3, the most excellent value, which was put down to the high density and relatively fine grains. The results of this study have a better knowledge of the ASHM method to produce a high surface state and mechanical behavior 316L SS component by governing laser energy density (ψ).
关键词： Additive/subtractive hybrid manufacturing,Laser energy density,Microstructure,Densification,Vickers microhardness,Tensile properties
更新于2025-09-16 10:30:52