纳米切削单晶铜的准连续介质法模拟

Quasicontinuum simulation of nanometric cutting of single crystal copper

采用准连续介质多尺度方法模拟了单晶铜的纳米切削过程。分别采用原子位置图和应力分布图对纳米切削过程中局部变形进行描述,得出了模型的切削力-切削距离的响应曲线。从微观角度分析了单晶铜纳米切削过程中材料变形、材料去除机理及内部损伤情况。根据模拟结果,对切削过程中位错形核、演化过程、湮灭消失、切屑及加工表面的形成过程进行了深入的分析。从位错演化的角度解释了切削力与应变能曲线的峰谷变化。提出了纳米切削过程中材料受到刀具的挤压作用而导致位错形核。得出了在纳米切削过程中塑性材料的去除是基于位错运动演化的结论。

The nanometric cutting process of the single crystal copper was simulated by the quasicontinuum multi-scale method. The diagrams of atomic positions and stress distributions were used to describe the local deformation in the nanometric cutting process to get the response curve of the cutting force versus cutting distance in the process. The atomic details of material deformation, material removal and internal damage in the process were analyzed microscopically. According to the simulation results, the dislocation nucleation, the evolution process, the vanishment of dislocations, the formations of cutting chips and newly generated surfaces were analyzed deeply in atomic level. The fluctuations of cutting force and strain energy were explained by evolution of dislocation movement. It was concluded that the compression in cutting zone ahead of cutting edge in the nanometric cutting process led to dislocation nucleation, and the removal of plastic material in the process resulted from the evolution of dislocations