Molecular Dynamics Simulation to Investigate the Rake Angle Effects on Nanometric Cutting of Single Crystal Ni₃Al

Molecular dynamics, an effective method to gain an insight into nanometric behaviour of materials, was employed to study the nano-cutting behaviour of single crystal Ni₃Al in nanometric scale. In this paper, comparisons were made for compressive/tensile stress, subsurface damage and surface roughness with three rake angles of a diamond tool. Subsurface damage was partitioned by region and studied with work hardening in detail. A model for precise characterization of surface roughness was established with consideration of local surface fluctuation. Simulation results showed that the chip thickness increased as rake angle changed from negative to positive, and the boundary formed between tensile and compressive stress was in consistent with the glide direction of stacking fault. Subsurface damage decreased as the increase of rake angle, and regular glide planes of stacking faults were found in front of the cutting tool. Further, the pinned dissociated 1/2 < 110 > superpartial dislocation with anti-phase boundary was demonstrated. The model was tested and characterized by implanted pits on perfect surface. Results showed that surface roughness can be well characterized, and an evident discrepancy was observed among three rake angles, especially for 30° rake angle, which showed an distinct smooth surface compared with the others.