Molecular dynamics simulation of the tribological performance of amorphous/amorphous nano-laminates

Because the amorphous/amorphous nano-laminates could enhance significantly the mechanical properties of the amorphous materials, they have been widely studied as a new group of structural materials. In this study, the nano-scratch performance of the Cu₈₀Zr₂₀/Cu₂₀Zr₈₀ (A/B-type) and the Cu₂₀Zr₈₀/Cu₈₀Zr₂₀ (B/A-type) amorphous/amorphous nano-laminates was evaluated by molecular dynamics simulation. Their dependences on the type of indenter, layer thickness, stacking mode and scratch depth were systematically analyzed. There is a significant size effect for the tribological properties of amorphous/amorphous nanolaminates that the friction force of the A/B-type increases with the increase of layer thickness, but the friction force of the B/A-type decreases as the layer thickness increase. The interface has an obvious obstruction effect on the shear deformation and reduces the plastic affected region below the scratched groove. Particularly, the contact environment of the indenter bottom has an important influence on the normal force, so it's not that the deeper the depth, the greater the normal force. Hence it should not be ignored when evaluating the tribological properties of the amorphous/amorphous nano-laminates. This work can deepen the understanding of hetero-interface on the deformation mechanism during nano-scratch, and help to design amorphous nano-laminates with tailored tribological performance for practical applications.