Shear transformation zone dependence of creep behaviors of amorphous phase in a CuZr-based bulk metallic glass composite

The creep behaviors of the amorphous phase in a CuZr-based bulk metallic glass composite (BMGC) are studied by nano-indentation. Samples fabricated via higher cooling rates are found to exhibit more prominent creep, but a smaller shear viscosity. The volume of the shear transformation zones (STZs) in the amorphous phase calculated based on a cooperative shear model increases with the cooling rate. The evolution of excess free volume created during creep deformation is clarified. A looser atomic arrangement leads to a larger STZ volume, thus facilitating creep deformation. This study gives a better understanding of the deformation behaviors of the amorphous phase in BMGCs.