Wang Zhiguo, Chen Jiaxuan, Wang Guilian, Bai Qingshun, Liang Yingchun
School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, 150001, People's Republic of China.
College of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, People's Republic of China.
Nanoscale Res Lett. 2017 Dec;12(1):300. doi: 10.1186/s11671-017-2046-4. Epub 2017 Apr 26.
The anisotropy exhibited by single-crystal silicon in nanometric cutting is very significant. In order to profoundly understand the effect of crystal anisotropy on cutting behaviors, a large-scale molecular dynamics model was conducted to simulate the nanometric cutting of single-crystal silicon in the (100)[0-10], (100)[0-1-1], (110)[-110], (110)[00-1], (111)[-101], and (111)[-12-1] crystal directions in this study. The simulation results show the variations of different degrees in chip, subsurface damage, cutting force, and friction coefficient with changes in crystal plane and crystal direction. Shear deformation is the formation mechanism of subsurface damage, and the direction and complexity it forms are the primary causes that result in the anisotropy of subsurface damage. Structurally, chips could be classified into completely amorphous ones and incompletely amorphous ones containing a few crystallites. The formation mechanism of the former is high-pressure phase transformation, while the latter is obtained under the combined action of high-pressure phase transformation and cleavage. Based on an analysis of the material removal mode, it can be found that compared with the other crystal direction on the same crystal plane, the (100)[0-10], (110)[-110], and (111)[-101] directions are more suitable for ductile cutting.
单晶硅在纳米切削中表现出的各向异性非常显著。为了深入理解晶体各向异性对切削行为的影响，本研究建立了大规模分子动力学模型，对单晶硅在(100)[0-10]、(100)[0-1-1]、(110)[-110]、(110)[00-1]、(111)[-101]和(111)[-12-1]晶向的纳米切削进行模拟。模拟结果表明，随着晶面和晶向的变化，切屑、亚表面损伤、切削力和摩擦系数呈现出不同程度的变化。剪切变形是亚表面损伤的形成机制，其形成的方向和复杂性是导致亚表面损伤各向异性的主要原因。从结构上看，切屑可分为完全非晶态切屑和含有少量微晶的不完全非晶态切屑。前者的形成机制是高压相变，后者是在高压相变和劈裂的共同作用下形成的。通过对材料去除模式的分析发现，与同一晶面上的其他晶向相比，(100)[0-10]、(110)[-110]和(111)[-101]方向更适合延性切削。
