Varying the treating conditions to rejuvenate metallic glass by deep cryogenic cycling treatment

In this study, the effects of various experimental conditions on the rejuvenation behavior of a Zr-based metallic glass during deep cryogenic cycling treatment have been evaluated. It is found that the cooling/heating cycling treatment and the final cryogenic temperature play the key roles in the rejuvenation rather than cooling/heating rates. A lower cryogenic temperature during cycling can rejuvenate the glass to a higher energy state because of the higher internal stress generated. The hardness and plasticity of more rejuvenated samples were found to be lower and better than those less rejuvenated ones, respectively, which may originate from the more induced free volume that makes the atomic packing much looser and consequently facilitates the formation of more shear bands. Furthermore, the shear transformation zone size in the more rejuvenated samples was found to be larger than those less rejuvenated ones, which also contributes to the overall plasticity. (C) 2019 Elsevier B.V. All rights reserved.