Molecular dynamics simulation of silicon carbide nanoscale material removal behavior
Molecular dynamics simulation of silicon carbide nanoscale material removal behavior
复制标题
碳化硅纳米级材料去除行为的分子动力学模拟
DOI：
10.1016/j.ceramint.2018.03.195
复制
发表时间：
2018-07-01
影响因子：
5.2
通讯作者：
Kong, Lingfei
中科院分区：
文献类型：
--
作者：
Liu, Yao;Li, Beizhi;Kong, Lingfei
采用分子动力学模拟方法研究了金刚石磨粒对单晶和多晶碳化硅（SiC）的刮擦过程，以探讨纳米材料的去除行为。结果表明，单晶和多晶SiC材料的去除过程都是通过向非晶结构的相变实现的。大的切削深度和低的刮擦速度导致大的刮擦力、应力和表面损伤层厚度。与单晶SiC相比，多晶SiC的非晶结构相变较少，法向划痕力较小，切向应力较高，这是由于多晶SiC的微观结构导致材料软化所致。此外，切向应力表现出高度依赖于晶粒的几何形状和晶界（GB）的位置在多晶。在低切削深度下，多晶的亚表面损伤层比新一代GB前的单晶的亚表面损伤层稍薄，而在大切削深度下，亚表面损伤层恶化。除了单晶SiC纳米级划痕中发生的塑性变形外，多晶SiC中还通过GB的生成和连接发生了沿晶断裂和穿晶断裂。
The scratching processes of monocrystalline and polycrystalline silicon carbide (SiC) with diamond grit were studied by molecular dynamics simulation to investigate the nanoscale material removal behavior. The results showed that, for both monocrystalline and polycrystalline SiC, the material removal processes were achieved by the phase transition to the amorphous structure. Large depth of cut and low scratching speed induced the large scratching forces, stress, and surface damage layer thickness. Less amorphous structure phase transition, smaller normal scratching force, and higher tangential stress were found in polycrystalline SiC, comparing to the monocrystalline SiC, due to the material soften caused by the microstructure, under all scratching conditions. Furthermore, the tangential stress showed highly dependent on the grain geometry and grain boundary (GB) location in polycrystalline. The subsurface damage layer in polycrystalline was little thinner than that in monocrystalline before the new GB generation at a low depth of cut and deteriorated at large depth of cut. In addition to the plastic deformation, which occurred in the monocrystalline SiC nanoscale scratching, the intergranular fracture and transgranular fracture were also observed through the GB generation and connection in polycrystalline SiC.