Subsurface damage of single crystal nickel by micro-nanometric cutting with diamond tool

Abstract

The micro-dynamic process of diamond tool micro-nanometric cutting single crystal nickel was studied by molecular dynamics software Lammps. The types of defects, the relationship between cutting force and damage, and the evolution of dislocation lines during micro-nanometric cutting of single crystal nickel under different cutting directions and depths were analyzed. The results show that the high pressure phase transition zone and amorphous zone are formed in the single crystal nickel workpiece due to the extrusion and shearing of the tool, and there are atomic clusters and dislocation slip in the subsurface layer. The cutting along the [100] crystal direction has the smallest cutting force and the minimum thickness of the dislocation damage layer is 2.15 nm. The cutting along the [111] crystal direction has the best surface layer quality, but the maximum thickness of the damage layer is 3.75 nm. In the cutting process, the total length of dislocation line presents an overall upward trend, and the atom region removed in [110] direction as well as the dislocation line length are the largest. The greater the cutting depth is, the more serious the dislocation slip and the amorphous in the crystal become.

Keywords

• molecular dynamics
• single crystal nickel
• micro-nanometric cutting
• damage
• cutting force
• dislocation line