Effect of Fluid Media on Material Removal and Subsurface Defects Evolution of Monocrystal Copper in Nano-Cutting Process

摘要

The effect of fluid media on material removal and subsurface defects evolution in nano-cutting process of single-crystal copper is investigated by means of molecular dynamics simulation. In this paper, the removal mechanism of the chip and formation mechanism of machined surface are investigated by analyzing the atomic migration and dislocation evolution of workpiece during nano-cutting process with the use of aqueous media. The distribution of temperature and subsurface defect crystal structural transformation are investigated, which are analyzed by centro-symmetry parameter and common neighbor analysis methods. The results show that the workpiece material is removed by the extrusion shearing action of the cutting tool. The lubrication of the aqueous media can reduce the cutting force and lower the height of cutting chip. Particularly, the cooling action of the fluid media results in the formation of a typical defect “similar-to-grain boundary” in subsurface of the workpiece. And the temperature of workpiece has a distinct decrease during nano-cutting process with the use of fluid media.