Macroscopic viscoelastic deformation at room temperature in mechanically rejuvenated Zr-based metallic glass

By employing mechanical rejuvenation, we demonstrated that the viscoelastic deformation become visible in macroscopic tensile test. The clear tensile strain rate dependence of yield stress was observed only in the rejuvenated sample, showing that the macroscopic elongation is governed by the thermally activated process. Activation volumes estimated from the mechanical responses during the macroscopic tensile test and microscopic nanoindentation test showed consistent values. The rejuvenated sample having tensile ductility showed larger STZ volume comparing with the relaxed samples. These results indicate that the fraction and connectivity of liquid-like regions in BMG can be controlled by appropriate use of mechanical rejuvenation.