Characteristics of atomic removal and mechanism of damage formation in vibration-assisted nano cutting of copper-nickel alloy

Abstract

Vibration-assisted machining technology can effectively improve the quality and efficiency of nano cutting, but the characteristics of atomic removal and the mechanism of damage formation have not been systematically studied. In this paper, copper-nickel alloy material is taken as an example. The characteristics of vibration-assisted nano cutting and the plastic deformation behavior of materials were revealed by molecular dynamics simulation. The simulation results show that vibration-assisted nano cutting reduces tangential force, lateral force, and total force, strengthens the anisotropy of atomic motion, and causes greater displacement and removal of Cu/Ni atoms. The intermittent contact is beneficial for the elastic recovery of workpiece atoms, releasing internal stress and atomic strain, reducing the depth of damage and the length of dislocation lines. The difference in surface/subsurface damage to the workpiece is relatively small with an amplitude of 1 Å. With amplitudes of 3 Å and 5 Å, and as the frequency increases, the complete lattice structure is destroyed, resulting in a significant decrease in the number of FCC structural atoms and RDF peak. However, an appropriate increase in frequency can increase the removal of Cu/Ni atoms, improve the topological structure, and reduce RMS. The HCP and BCC structural atoms affect the generation of dislocation lines, with an amplitude of 3 Å and a frequency of 7.5 GHz, achieving the minimum damage depth and dislocation line length. Excessive amplitude of 10 Å results in irreversibly severe damage to the surface/sub-surface of the workpiece. This study will provide a new approach for optimizing vibration-assisted nano-cutting technology and achieving low-damage nano cutting of alloy materials.