Effect of abrasive size on nano abrasive machining for wurtzite GaN single crystal via molecular dynamics study

Abstract

Molecular dynamics simulations were used to explore the effect of abrasive size on the nano abrasive machining for wurtzite gallium nitride (GaN) single crystal. The deformation behaviours, varied with the abrasive size, were systematically analysed. The simulation results show that increasing the abrasive size results in more severe plastic deformation and machining-induced hardening, which consequently cause an increase in atomic temperature, strain, stress, and cutting forces. The use of larger abrasive produces greater compression, thus boosts the elastic recovery and damages the subsurface of GaN single crystal much heavily, with the enhancement of the nucleation and emission of dislocation, and the local phase transition from B4 to B3 structure or even to fivefold hexagonal structure. The development of pile-up and amorphization is impressively inhibited by increasing abrasive size, suggesting that the cutting effect could be impaired using a larger abrasive under a given depth of cut.