Origins of ductile plasticity in a polycrystalline gallium arsenide during scratching: MD simulation study
Origins of ductile plasticity in a polycrystalline gallium arsenide during scratching: MD simulation study
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DOI：
10.1016/j.apsusc.2021.149489
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发表时间：
2021-03-13
影响因子：
6.7
通讯作者：
He, Yang
中科院分区：
文献类型：
--
作者：
Fan, Pengfei;Goel, Saurav;He, Yang
采用分子动力学模拟方法研究了多晶砷化镓（GaAs）纳米划痕过程中延性塑性的起源。利用金刚石工具进行了速度控制的纳米划痕实验，研究了多晶GaAs的摩擦变形行为。切削温度，亚表面损伤深度，切削应力，位错的演变和随后的微观结构的变化提取从模拟。模拟的MD数据表明，多晶GaAs的变形伴随着晶界（GB）中的位错成核，导致塑性变形的开始。此外，1/2？一百一十？是多晶GaAs中延性塑性的主要位错类型。切削力的大小和亚表面损伤的程度都观察到减少与划痕速度的增加，而切削温度与切削速度成比例。对于划痕的深度，其幅度的增加了切削力，温度和损伤深度。只有在切割多晶GaAs时才观察到切割力从波峰到波谷的波动现象，而在切割单晶GaAs时没有观察到这种现象。
This paper used molecular dynamics simulation to reveal the origins of the ductile plasticity in polycrystalline gallium arsenide (GaAs) during its nanoscratching. Velocity-controlled nanoscratching tests were performed with a diamond tool to study the friction-induced deformation behaviour of polycrystalline GaAs. Cutting temperature, sub-surface damage depth, cutting stresses, the evolution of dislocations and the subsequent microstructural changes were extracted from the simulation. The simulated MD data indicated that the deformation of polycrystalline GaAs is accompanied by dislocation nucleation in the grain boundaries (GBs) leading to the initiation of plastic deformation. Furthermore, the 1/2?110? is the main type of dislocation responsible for ductile plasticity in polycrystalline GaAs. The magnitude of cutting forces and the extent of sub-surface damage were both observed to reduce with an increase in the scratch velocity whereas the cutting temperature scaled with the cutting velocity. As for the depth of the scratch, an increase in its magnitude increased the cutting forces, temperature and damage-depth. A phenomenon of fluctuation from wave crests to wave troughs in the cutting forces was observed only during the cutting of polycrystalline GaAs and not during the cutting of single-crystal GaAs.