Creep recovery of stress-annealed Zr-based metallic glass: Investigation based on the dynamic viscoelastic model

An isochronal creep recovery of a Zr-based material is discussed with a constructed dynamic viscoelastic model based on the Maxwell model concerning structural heterogeneity and relaxation. Creep strain retention occurs when elastically deformed and plastically deformed regions with long and short relaxation times, respectively, coexist upon stress-annealing treatment. Subsequently, the residual creep strain is released when relaxation is activated sequentially from the relaxation sites with the lowest activation energy during reheating. Stressannealing temperature and time can affect the creep strain recovery magnitude and peak temperature for the corresponding strain rate, whereas the stress-annealing stress only affects the creep recovery magnitude. Therefore, this dynamic viscoelastic model offers new perspectives toward the understanding of metallic glasses.