Relaxation and Strain-Hardening Relationships in Highly Rejuvenated Metallic Glasses

One way to rejuvenate metallic glasses is to increase their free volume. Here, by randomly removing atoms from the glass matrix, free volume is homogeneously generated in metallic glasses, and glassy states with different degrees of rejuvenation are designed and further mechanically tested. We find that the free volume in the rejuvenated glasses can be annihilated under tensile or compressive deformation that consequently leads to structural relaxation and strain-hardening. Additionally, the deformation mechanism of highly rejuvenated metallic glasses during the uniaxial loading-unloading tensile tests is investigated, in order to provide a systematic understanding of the relaxation and strain-hardening relationship. The observed strain-hardening in the highly rejuvenated metallic glasses corresponds to stress-driven structural and residual stress relaxation during cycling deformation. Nevertheless, the rejuvenated metallic glasses relax to a more stable state but could not recover their initial as-cast state.

Automated summary

Increasing free volume in metallic glasses rejuvenates them, but this free volume can be annihilated under deformation leading to structural relaxation and strain-hardening. Highly rejuvenated metallic glasses experience stress-driven structural and residual stress relaxation during cycling deformation, eventually reaching a more stable state but unable to recover their initial state.