Strain Rate Dependent Shear Banding Deformation in Al/W Nanomultilayers

Abstract

A serial of Al/W multilayers with equal and unequal individual layer thickness were prepared by direct current magnetron sputtering technology. Hardness and shear banding deformation behavior was investigated by nanoindentation at various applied strain rates. The results showed that the Al/W multilayers exhibit positive strain rate sensitivity of hardness, and the magnitude of strain rate sensitivity changed at various applied strain rates. Moreover, shear bands can only be observed in the multilayers with certain individual layer thickness, and the number of shear band increases with applied strain rate. The changes of orientation between neighboring grains upon indentation penetration are proposed to be the dominant mechanism in forming shear bands, and the effect of lattice structure and other deformation mechanisms were extended discussed.