单晶锗纳米切削过程分子动力学仿真与实验研究

Molecular dynamics simulation and experimental study of single crystalline germanium cutting process

摘要:

为深入理解单晶锗纳米切削特性,提高纳米锗器件光学表面质量,采用三维分子动力学(MD)模拟方法研究了单点金刚石压头与单晶锗表面的接触和滑动过程。研究了压头在滑动切削过程中的材料变形、切削力、切屑堆积、表面形貌尺寸。仿真结果表明,随着垂直载荷的增加,切削力、表面形貌尺寸、切屑堆积在接触过程中逐渐增加,且与切削速度无明显关联。切削过程中切削力波动的根本原因是由于单晶锗晶格破坏引起位错的产生和能量波动。为了验证仿真结果的正确性,使用纳米划痕仪对单晶锗进行了纳米切削实验。实验结果与仿真结果一致,验证了MD模型的正确性和有效性。

Abstract:

In order to understand the nanoscale cutting characteristics of single crystal germanium and improve the optical surface quality of the nanoscale germanium, three-dimensional molecular dynamics (MD) simulations were carried out to study the contact and sliding processes between diamond points and surfaces of single crystal germanium. The material deformation, cutting force, chips pile-up, surface morphology size, and the sliding friction process were investigated. The simulation results show that the cutting force, surface morphology size, and chips plie-up, increase during the contact process with increasing vertical force, and there is no obvious correlation with the cutting speed. The fundamental reason for the fluctuation of the cutting force in the cutting process is caused by the generation of dislocation and the energy fluctuation caused by the destruction of the lattice of single crystal germanium. In order to verify the correctness of the simulation results, nanometer cutting experiments on single crystal germanium were carried out using nano-scratch tester. The experimental results are in agreement with the simulation results, which verify the correctness and effectiveness of the MD model.