Tensile Plasticity in Metallic Glasses with Pronounced β Relaxations

Metallic glasses are commonly brittle, as they generally fail catastrophically under uniaxial tension. Here we show pronounced macroscopic tensile plasticity achieved in a La-based metallic glass which possesses strong beta relaxations and nanoscale heterogeneous structures. We demonstrate that the beta relaxation is closely correlated with the activation of the structural units of plastic deformations and global plasticity, and the transition from brittle to ductile in tension and the activation of the beta relaxations follow a similar time-temperature scaling relationship. The results have implications for understanding the mechanisms of plastic deformation and structural origin of beta relaxations as well as for solving the brittleness in metallic glasses.