Effect of precipitate shape and distribution on mechanical behavior of shape memory metallic glass composites by molecular dynamics method

The deformation behaviors of metallic glass composites enhanced with brick and cylindrical shape B2-CuZr precipitates were investigated by molecular dynamics method. Both specimens experience a two-stage phase transformation and triple-yielding phenomenon. The brick-shaped precipitate enhanced bulk metallic glass composite (BMGC) exhibits significantly improved strength and mildly enhanced plasticity compared to cylindrical shape inclusion reinforced BMGC. The larger aspect ratio of brick-shaped precipitate enhanced BMGC strengthens the composite by improving elastic lattice deformation along loading direction, while the enhanced plasticity is ascribed to smaller free path for mature shear bands formation. The deformation mechanism for brick-shaped BMGCs is shear band cutting through precipitates, while that for cylindrical shape precipitate reinforced BMGCs is shear band wrapping around crystalline particles. Both specimens display high strain at crystalline/amorphous interface (CAI) region and might experience interfacial stability issue.