Nanometric cutting mechanism of cerium-lanthanum alloy

Abstract

Molecular dynamics (MD) simulation is an effective approach to reveal the atomic-scale details of the material removal mechanism in nanometric cutting. In this study, through a MD simulation, we analyze the effects of cutting speed and cutting depth on cutting force and subsurface deformation of the cerium–lanthanum alloy during nanometric cutting. The results illustrate that the dislocations, stacking faults, and phase transitions occur on the material subsurface during the cutting process. The dislocations are mainly Shockley partial dislocation, and increasing the temperature and pressure during the cutting process leads to the transformation of γ-Ce (FCC) into β-Ce (HCP) and δ-Ce (BCC). β-Ce is mainly distributed in the stacking fault area, while δ-Ce is distributed in the boundary area between the dislocation atoms and γ-Ce atoms. The cutting speed and cutting depth are important factors affecting the distribution of subsurface damage. A thicker subsurface deformed layer on the machined surface, comprising dislocations, stacking faults, and lattice defects, is generated with an increase in the cutting speed and cutting depth. Simultaneously, the cutting speed and cutting depth significantly affect the cutting force, material removal rate, and generated subsurface state. The fluctuations in the cutting force are related to the generation and disappearance of dislocations. The higher the cutting speed and the deeper the cutting depth, the more phase-transition atoms on the subsurface.