Plastic deformation due to interfacial sliding in amorphous/crystalline nanolaminates

Abstract Molecular dynamics simulation was used to study the properties of the amorphous Cu46Zr54/crystalline interface and their effects on mechanical responses. Structural heterogeneity was observed in the Cu46Zr54 layer in both an as-quenched and a separately quenched sample. Based on the simulation results, a new multi-yielding scenario for the formation of shear transformation zones (STZs), interfacial sliding, thickening of micro-sliding bands and lattice dislocation is proposed. During shear deformation, both samples first yielded due to the formation of STZs in the amorphous layers. After the formation of the STZs, micro-sliding bands with highly localized atomic shear strain formed in both samples via different interfacial mechanisms: via the growth of STZs at the amorphous/crystalline interfaces (ACIs) in the separately quenched sample, and via the spreading of the dislocation loop at the ACIs in the as-quenched sample. The thickening of micro-sliding bands on an amorphous layer via internal friction is identified as a new plastic deformation mechanism under appropriate loading conditions. The thickening rate in the as-quenched sample was higher than that in the separately quenched sample. The crystalline layer finally yielded due to partial dislocation slip. An analytical model suggests that this new multi-yielding scenario should be expected to operate in bulk metallic glass-based composites.Department of Mechanical Engineerin