金刚石刀具微纳米切削单晶镍亚表面损伤

Subsurface damage of single crystal nickel by micro-nanometric cutting with diamond tool

采用分子动力学软件Lammps研究金刚石刀具微纳米切削单晶镍的微观动态过程,分析不同切削方向和不同切削深度下单晶镍微纳米切削过程中缺陷的类型、切削力和损伤的关系以及位错线的演化规律。结果表明:刀具的挤压和剪切作用使单晶镍工件产生高压相变区和非晶区,其亚表层存在原子团簇和位错滑移。沿[100]晶向切削,切削力最小,且位错损伤层厚度最小为2.15 nm;沿[111]晶向切削,表面层的质量最好,但损伤层厚度最大为3.75 nm。切削过程中,位错线的总长度整体呈上升趋势,[110]方向去除的原子区域最大,位错线长度最大。切削深度越大,晶体内部的位错滑移和非晶化越严重。

The micro-dynamic process of diamond tool micro-nanometric cutting single crystal nickel was studied by molecular dynamics software Lammps.The types of defects,the relationship between cutting force and damage,and the evolution of dislocation lines during micro-nanometric cutting of single crystal nickel under different cutting directions and depths were analyzed.The results show that the high pressure phase transition zone and amorphous zone are formed in the single crystal nickel workpiece due to the extrusion and shearing of the tool,and there are atomic clusters and dis-location slip in the subsurface layer.The cutting along the[100]crystal direction has the smallest cutting force and the minimum thickness of the dislocation damage layer is 2.15 nm.The cutting along the[111]crystal direction has the best surface layer quality,but the maximum thickness of the damage layer is 3.75 nm.In the cutting process,the total length of dislocation line presents an overall upward trend,and the atom region removed in[110]direction as well as the dislo-cation line length are the largest.The greater the cutting depth is,the more serious the dislocation slip and the amorph-ous in the crystal become.