Tunable rejuvenation behavior of a metallic glass by residual stress modulation

In this study, the structure changes and related mechanical properties of the Zr61Ti2Cu25Al12 metallic glass treated by triaxial compression and followed by further cryogenic thermal cycling were systematically studied. It is found that the structure evolution based on the changes in the relaxation enthalpy and diffraction peak position shows inconsistencies with each other. Vickers hardness mapping reveals that residual stresses may impart and store in the extremely deformed metallic glass sample, which can be verified from the change of hardness and that can well explain such inconsistencies. As thermal cycling proceeds, the stored residual stresses will relieve and compete with structure softening from the process of thermal cycling, leading to a tunable rejuvenation behavior. A plausible model that correlates rejuvenation and thermal-mechanical protocols is proposed. This work highlights that residual stress plays a vital role in the metallic glass rejuvenation and should be taken into account, which may be helpful for the design of metallic glasses with desired mechanical performance