Two different types of shear-deformation behaviour in Au-Cu multilayers

Localised shear deformation of a material is usually identified as a particular feature of deformation inhomogeneity. Here, we show two different types of shear deformation-behaviour that occurred in Au-Cu multilayers subjected to microindentation load, namely, a cooperative-layer-buckling-induced shear banding in a nanoscale multilayer and a direct localised shearing across a layer interface along a shear plane in a submicron-scale multilayer. Theoretical analysis indicates that the formation of the two different types of shear deformation in the multilayers depends on a competition between the dislocation-pile-up-induced stress concentration at the layer interface and the barrier strength of the layer interface for glissile dislocation transmission.