Deformation and evolution of shear bands under compressive loading in bulk metallic glasses

Shear band formation and failure mechanism in monolithic glasses and glass matrix composite exhibiting a wide range of plasticity were investigated by interrupted compression experiments. The major shear bands in monolithic glasses appear rapidly after a small deformation, and their numbers remain almost same in the later stages of deformation. The path of the crack growth does not coincide strictly with the shear band. The larger plastic strain in glasses exhibiting higher ductility is mainly accommodated in the primary shear band by forming larger shear offset prior to failure. The failure mechanism under compression is not pure shear, but mixed mode with evidence of a tensile component, which leads to the formation of microvoids (microcracks). Bridging of the microvoids leads to final fracture. In the case of glass composite containing particles, the microcracks at the interface arrest the propagation of the existing shear bands and form additional shear bands, improving plasticity.