Work-hardenable Mg-based bulk metallic glass matrix composites reinforced by ex-situ porous shape-memory-alloy particles

Porous NiTi shape-memory-alloy particle-reinforced Mg-based bulk metallic glass matrix composites were prepared by an ex-situ method. The composites show a larger plastic strain, higher fracture strength and obvious work-hardening behavior compared with their monolithic glassy counterparts. The ex-situ porous NiTi particles hinder the rapid propagation of shear bands, which generates multiplied shear bands, like other ductile metal particles, and undergo a stress-induced martensitic transformation, which is unique and contributes to work hardening. Local regions within one porous particle satisfy the optimal conditions of bulk metallic glass matrix composite structure, i.e., the average particle size and mean inter-particle spacing are close to the processing zone size, and thereby further improve the plasticity by localized plastic deformation.