Structural relaxation in metallic glasses (MGs) occurs when the material is annealed at elevated temperatures , resulting in substantial property change in MGs, including diffusivity , plasticity , electrical resistivity , and son on. The free volume (FV) model can explain the structural relaxation in BMG. According to the FV model, structural relaxation at the elevated temperatures is resulted from a reduction of the excess free volume that was trapped in the MG during material processing . A direct evidence for the free volume reduction during structural relaxation is the densification experiment performed by Haruyama [6–8]. Different models have been proposed to interpret the structural relaxation behavior, for instance, flow defect model [9-10], stretched exponential relaxation model, Šesták–Berggren SB (m, n) kinetic model, and isothermal–isoconversional method.
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