Distinct relaxation mechanism at room temperature in metallic glass

How glasses relax at room temperature is still a great challenge for both experimental and simulation studies due to the extremely long relaxation time-scale. Here, by employing a modified molecular dynamics simulation technique, we extend the quantitative measurement of relaxation process of metallic glasses to room temperature. Both energy relaxation and dynamics, at low temperatures, follow a stretched exponential decay with a characteristic stretching exponent beta=3/7, which is distinct from that of supercooled liquid. Such aging dynamics originates from the release of energy, an intrinsic nature of out-of-equilibrium system, and manifests itself as the elimination of defects through localized atomic strains. This finding is also supported by long-time stress-relaxation experiments of various metallic glasses, confirming its validity and universality. Here, we show that the distinct relaxation mechanism can be regarded as a direct indicator of glass transition from a dynamic perspective.

Automated summary

By using a modified molecular dynamics simulation technique, we successfully extend the quantitative measurement of relaxation process of metallic glasses to room temperature and find that the energy relaxation and dynamics at low temperatures follow a stretched exponential decay. This aging dynamics originates from the release of energy and the elimination of defects through localized atomic strains. Long-time stress-relaxation experiments of various metallic glasses support this finding and confirm its validity and universality. Thus, the distinct relaxation mechanism can be regarded as a direct indicator of glass transition from a dynamic perspective.