Shear-band evolution and plasticity enhancement of metallic glass composites investigated by molecular dynamics simulations

Metallic glass composites (MGCs) with an amorphous-crystalline dual-phase structure can display remarkable mechanical properties. However, the cooperative deformation mechanisms of both phases and the shear band (SB) evolution in MGCs still remain elusive. In this work, the deformation behaviors of MGCs containing phase-transformable or dislocation-mediated crystals are thoroughly investigated by molecular dynamics simulations. It is found that the SB dynamics can be significantly altered by the stress concentration caused by notches and the deformation characteristics of the crystals. Notch-induced stress redistribution can enhance the shear-band blunting degree and promote the formation of multiple SBs, which highly delocalize the plastic deformation of the phase-transformable MGCs and optimize their ductility. In comparison, introducing notches cannot alter the highly localized shear banding mechanism in the dislocation-mediated MGCs. These findings deepen the atomic-level understanding of the cooperative deformation mechanisms of both phases and the SB evolution in MGCs.