Study on the Nano-Friction Behavior of Nickel-Based Ag Film Composites Based on Molecular Dynamics

Abstract

The nano-friction behavior of nickel-based Ag film composites was evaluated using molecular dynamics simulations. The mechanical properties, the surface morphology, the migration behavior of Ag atoms and the defect evolution during repeated friction were investigated. Our results show that the poor mechanical properties of the Ag film surface at the first stage of friction are related to a large amount of abrasive chip pileup. The slip channel with low shear strength formed by secondary friction significantly reduces the friction coefficient of the Ag film surface. Meanwhile, the migration of Ag atoms at the two-phase interface relies mainly on the repeated friction of the grinding ball, and the friction coefficient of the nickel surface decreases as the number of migrating atoms increases. In addition, the extension of defects inside the Ag film and atomic displacement is hindered by the two-phase interface. The defects inside the Ag film near the friction zone gradually evolve from an intrinsic stacking fault to a horizontal stacking fault as the friction proceeds. This is attributed to the horizontal layer-by-layer motion of Ag atoms, promoting the formation of horizontal stacking faults.