Transient nature of fast relaxation in metallic glass

Metallic glasses exhibit fast mechanical relaxations at temperatures well below the glass transition, one of which shows little variation with temperature known as nearly constant loss (NCL). Despite important implications this phenomenon to deformation, origin relaxation is unclear. Through molecular dynamics simulations a model metallic glass, Cu64.5Zr35.5, we implement dynamical spectroscopy (MD-DMS) system stress decomposed into atomic-level stresses identify group atoms responsible for NCL. This work demonstrates that NCL due transient groups revert typical viscoelastic behavior over picosecond timescales. They are homogenously distributed throughout and have no outstanding features, rather than having defect-like local structure previously reported.