This paper aims to reveal the mechanism for improving ductile machinability of 3C-silicon carbide (SiC) and associated cutting mechanism in stress-assisted nanometric cutting.
Molecular dynamics simulation of nano-cutting 3C-SiC is carried out in this paper. The following two scenarios are considered: normal nanometric cutting of 3C-SiC; and stress-assisted nanometric cutting of 3C-SiC for comparison. Chip formation, phase transformation, dislocation activities and shear strain during nanometric cutting are analyzed.
Negative rake angle can produce necessary hydrostatic stress to achieve ductile removal by the extrusion in ductile regime machining. In ductile-brittle transition, deformation mechanism of 3C-SiC is combination of plastic deformation dominated by dislocation activities and localization of shear deformation. When cutting depth is greater than 10 nm, material removal is mainly achieved by shear. Stress-assisted machining can lead to better quality of machined surface. However, there is a threshold for the applied stress to fully gain advantages offered by stress-assisted machining. Stress-assisted machining further enhances plastic deformation ability through the active dislocations’ movements.
This work describes a stress-assisted machining method for improving the surface quality, which could improve 3C-SiC ductile machining ability.
The study is supported by National Natural Science Foundation of China (NSFC)-German Research Foundation (DFG) International Joint Research Programme (51761135106), National Natural Science Foundation of China (No. 51575389, 51511130074), National Key Research and Development Program of China (2016YFB1102203), State key laboratory of precision measuring technology and instruments (Pilt1705) and the “111” project by the State Administration of Foreign Experts Affairs and the Ministry of Education of China (Grant No. B07014). The authors thank Prof. Chao Wang, Dr. Bing Liu and Mr. Zhongdu He for valuable discussions.
Liu, L., Xu, Z., Tian, D., Hartmaier, A., Luo, X., Zhang, J., Nordlund, K. and Fang, F. (2019), "MD simulation of stress-assisted nanometric cutting mechanism of 3C silicon carbide", Industrial Lubrication and Tribology, Vol. 71 No. 5, pp. 686-691. https://doi.org/10.1108/ILT-03-2019-0096Download as .RIS
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