Shock compression of Cu x Zr100−x metallic glasses from molecular dynamics simulations

Abstract

The shock response of Cu x Zr100−x (x = 30, 50 and 70) metallic glasses (MGs) is characterized using large-scale molecular dynamics simulations. A wide range of piston velocities U p = 0.125–2.5 km/s are simulated corresponding to shock pressures from 3 to 130 GPa. Independent of composition, the metallic glasses exhibit the following shock wave propagation regimes: (1) single elastic shock wave for U p < 0.25 km/s, (2) split elastic and plastic shock waves for 0.25 < U p < 0.75 km/s and (3) overdriven plastic shock wave with a narrow elastic precursor for U p > 0.75 km/s. Within the split wave and overdriven regimes, the amplitude of the elastic precursor increases with increasing shock intensity, thereby indicating a pressure-dependent yield criterion. Hugoniot states are strongly dependent on the Cu content of the MG with Cu70Zr30 exhibiting a much higher resistance to plastic deformation than either Cu50Zr50 or Cu30Zr70.