纳米磨削过程中加工表面形成与材料去除机理的分子动力学仿真

Mechanism of Material Removal and Surface Generation by Molecular Dynamics Analysis in Abrasive Processes

目前 ,以线性断裂力学为基础的加工理论对解释微切削加工机理还存在不足 .分子动力学分析的方法在研究纳米尺度或原子尺度下的固体变形方面具有独特的优势 ;辅以压痕挤压机理分析 ,解释纳米磨削过程中加工表面形成和材料去除机理 .研究表明 :静水压力对非结晶变形程度影响很大 ;晶格重构原子与一部分非晶层原子堆积在磨粒的前上方 ,由于磨粒不断前移 ,最终形成磨屑而实现材料去除 ,处在磨粒前下方的非晶层原子在压应力的作用下与已加工表层断裂的原子键结合重构形成已加工表面变质层 ;变质层由内外两层组成 ,外层是非晶层 。

At present, the machining theory based on the elasticity and fracture mechanics can not explain micro-machining mechanism completely. Molecular dynamics analysis has the particular advantage in researching the solid deformation of atom-scale area. It can aid in surveying the force features of grinding and indentation, stress state and grinding temperature and then explaining the micro-scale mechanism of the material remove and surface generation. The research shows: The atoms of the reconstituting crystal lattice and non-crystal lattice are piled up on the front of abrasive grain, with the continuous advancement of the abrasive grain, the material are removed; The hydrostatic stress has a great impact on the degree of the reconstituting crystal lattice and the formation of the non-crystal atoms; The degenerative layer of the finish surface are reconstituted by the severe deformation crystal lattice and the non-crystal atoms in the grinding surface, it consists of the outer non-crystal layer and the inner lattice deformation layer.