Enhancing the plasticity of a Ti-based bulk metallic glass composite by cryogenic cycling treatments

Abstract

The effect of cryogenic cycling treatments on the thermal and mechanical properties of a Ti-based bulk metallic glass (BMG) composite was investigated. Even though the macroscopic structures of the dendrite-phase and glass-matrix remain unchanged, the treated samples exhibited a rejuvenation behavior in terms of a higher relaxation enthalpy, which leads to an enhancement of plasticity as high as 90%. Different from the monolithic BMGs, in which rejuvenation has been attributed to the nanoscale structural heterogeneity, rejuvenation in BMG composite is induced by the crystal/amorphous heterogeneous microstructures. The increasing defects around the interfaces may promote formation of multiple shear bands and accommodation of plastic deformation. This work shows clearly that the cryogenic cycling treatments could be an effective and controllable way to modulate mechanical properties of BMG composites.