Shear-induced volumetric strain in CuZr metallic glass

The shear-induced volumetric strain (SIS) of a set of model CuZr metallic glasses is studied for various deformation conditions characterized by different strain rates, temperatures and applied hydrostatic stress states. The various systems considered are obtained by quenching from the melt at different cooling rates. During shear deformation at constant pressure, the material reaches a steady state in which the sample volume remains constant. It is observed that the density of the glass during steady state deformation depends on temperature, pressure and shear strain rate, and is independent of the initial state of the sample. The SIS vanishes as the temperature of the shear test reaches the glass transition temperature. The SIS can become negative under compressive pressure since the instantaneous bulk modulus is lowered by the shear flow. The results suggest that the magnitude of the SIS is related to the difference in density between samples quenched with given finite rate and a fictitious sample quenched infinitely fast.