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

Abstract

• The contribution of adhesion coefficient and ploughing coefficient to the total friction coefficient is clearly quantified by comparing the simulation results of virtual indenter and diamond indenter. • Through atomic visualization analysis, the blocking effect of interface on shear deformation during nano-scratch can be observed directly. • There is an obvious size dependence between friction force and layer thickness of amorphous/amorphous nano-laminates. • It's not that the deeper the penetration depth, the greater the normal force in 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 Cu 80 Zr 20 /Cu 20 Zr 80 (A/B-type) and the Cu 20 Zr 80 /Cu 80 Zr 20 (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. Graphical abstract .