Control of shear band formation in metallic glasses through introducing nanoscale pores

Abstract

The deformation behavior of porous metallic glasses with different pore shapes and porosity was investigated by molecular dynamics simulations. It is found that the elastic modulus and yield strength can be adjusted by pore shape and porosity. A transition of deformation modes in porous metallic glasses is observed with varying the pore shape and porosity. As the porosity increases the propagation direction of shear bands changes from the maximum shear stress direction (i.e. 45° to the loading direction) to perpendicular to the loading direction. The local strain parameter that characterizes strain localization decreases first and then increases with the porosity, reflecting a transition of deformation mode from localization to homogenization then back to localization. A continuous hardening is observed in compression tests as a consequence of gradual collapse of the pores from top to bottom. The pore shape plays an important role in the heterogeneous distribution of stress field.