Plastic deformation behaviours of CuZr amorphous/crystalline nanolaminate: a molecular dynamics study

The plastic deformation behaviours of Cu50Zr50/B2 CuZr amorphous/crystalline nanolaminate were studied at the atomic scale using molecular dynamics simulations. For pure metallic glass, the highly localised shear banding leads to the overall shear failure. And the plastic deformation of B2 CuZr crystal is mainly determined by the martensitic phase transformation. The composite material, nanolaminate, achieves great improvement of plastic deformation compared with the pure metallic glass and the pure crystal. This plasticity enhancement is attributed to two mechanisms: the suppression effect of the nucleation and propagation of the shear band and the regulating effect of the distribution of the shear transformation zones and phase transformation zones. The shear transformation zones can be induced by the interaction between phase transformation zones and interface. The immature shear band or shear transformations zones and phase transformation zones form a network to transmit the strain jointly within the entire sample. Amorphous/crystalline interface connects different layers and transmits the strain within the nanolaminate. Interfaces also plays the roles of source and sink of the shear transformation zones, shear band and phase transformation zones. On the basis of this plastic deformation mechanism, the present study provides a route for controlling the plasticity properties of amorphous/crystalline nanolaminate.