单晶SiC微切削机理分子动力学建模与仿真研究

Modeling and Simulation of Micro-cutting Mechanism of Single Crystal SiC by Molecular Dynamics

单晶Si C硬度高、脆性大,加工困难,在塑性域加工时处于纳米尺度才可明显改善表面质量、获得高的精度。而单晶Si C的切削机理研究使用有限元和实验方法,无法获得时间尺度在飞秒或皮秒下材料发生的变化。为此,采用分子动力学模拟方法,对单晶3C-Si C切削过程进行了建模和仿真,分析了在不同切削速度、切削深度下切削力的变化。研究结果表明:切削速度为50 m/s、100 m/s和200 m/s时对应的平均切向切削力为737.34 n N、635.29 n N和587.09 n N,单晶Si C表面采用合适的切削速度能减小切削过程的切削力。

Single crystal Si C has high hardness and brittleness,resulting in its processing difficulties.The surface quality and processing precision of single crystal Si C can be significantly improved only when it is processed in the nano-scale plastic range. At the nanoscale,however,the change of material at femtosecond/picosecond cannot be obtained using finite element and experimental methods. The molecular dynamics（ MD） is used to model the cutting process of single crystal 3 C-Si C. The cutting force is changed at different cutting speeds and depths. The results show that the average tangential cutting forces are737. 34 n N,635. 29 n N and 587. 09 n N at the cutting speeds of 50 m/s,100 m/s and 200 m/s,respectively,and an appropriate cutting speed is helpful to reduce the cutting force for the single crystal Si C.