Rejuvenation of Zr-based bulk metallic glass matrix composite upon deep cryogenic cycling

The rejuvenation behavior of Ta-rich particle reinforced Zr-based bulk metallic glass matrix composites upon deep cryogenic cycling treatment has been studied. The composite can be rejuvenated resulting in a higher enthalpy of relaxation and lower density. The internal stress generated from both the intrinsic heterogeneity in amorphous matrix and the interfaces between the matrix and Ta-rich phase should contribute to the rejuvenation behavior. The composite structure can generate a 4 times higher internal stress than that from the intrinsic heterogeneity, which causes the more rejuvenated state of the composites compared with the monolithic counterpart. With a higher volume fraction of Ta-rich phase, both the increment in enthalpy of relaxation and free volume between as-cast and thermal treated state increases almost linearly. The rejuvenated samples show better plasticity compared with as-cast counterparts because of more induced free volume.