Rejuvenation of a Zr-based metallic glass originates from strong icosahedral short-range order

Abstract

When a Zr-based metallic glass (MG) is stimulated by cryogenic thermal cycling (CTC), its atomic icosahedral short-range order (ISRO) has a crucial impact on the evolution of its energy state, determining whether the system undergoes relaxation or rejuvenation. Through experiments and molecular dynamic simulations, it was found that CTC increases the degree of structural heterogeneity in the MG with strong ISRO, thereby introducing more free volume, inducing its rejuvenation, and enhancing its plasticity. However, for the MG with weak ISRO, its response to CTC is completely opposite, that is, relaxation and densification occur. The response of CTC is highly sensitive to the initial atomic short-range order of MG. This finding provides some insights into achieving high rejuvenation of MGs from the perspective of atomic cluster structure.