Deformation mechanisms of the Zr40Ti14Ni10Cu12Be24 bulk metallic glass

We have studied the mechanical behavior of Zr40Ti14Ni10Cu12Be24 through uniaxial compression and nanoindentation experiments. Quantitative measurements of the serrated plastic flow observed during uniaxial compression are reported. These data are used to predict temperature increases in single shear bands due to local adiabatic heating caused by the work done on the sample as shear propagates progressively across the sample. Since the predicted temperature increases are insufficient to reach the glass transition temperature, it is unlikely that localized hearing is the primary cause of flow localization Instead, localization of shear is more likely caused by changes in viscosity associated with increased free volume in the sheer bands. The orientation of the shear bands in compression tests and an indentation size effect for the onset of plastic Bow in nanoindentation both point to increased free volume as the cause of localization.