Manipulation of relaxation processes in a metallic glass through cryogenic treatment

Abstract

The relaxation spectrum of glassy solids has long been considered to probe their structural features and deformation mechanisms. Here, by systematically investigating the structural evolution, dynamical relaxations and mechanical properties of a Zr-based metallic glass subjected to different cryogenic treatment time, we build a bridge to connect the relaxation processes and mechanical properties. It is found that the β-relaxation triggered by local excitations has no memory effect of the thermal history or initial free volume content of the system. However, some local denser areas with a high potential energy created by CT might contribute to β′-relaxation that activated at a much lower energy, which may play a crucial important role in the fundamental deformation mechanisms of metallic glasses. The relaxation behaviors and the related improved mechanical properties can be rationalized in terms of the atomic-level stress theory. These findings will advance our understanding of the intrinsic correlation between local excitations and mechanical properties of metallic glasses, thereby may help guide to develop amorphous alloys with high mechanical performance.