Cavitation instabilities in bulk metallic glasses

To reveal the mechanism of a void-dominated fracture process in bulk metallic glasses, a theoretical description of void growth undergoing remote hydrostatic tension is presented. Special attention is focused on cavitation instabilities and dynamics of a dynamic void growth process. The critical stress for cavitation instabilities is derived theoretically, which is validated by numerical simulations with a finite difference method. To characterize the dynamic void growth process, a dimensionless number is proposed, which embodies the competition of inertial effects, loading rate effects and viscous effects. It is found that inertial effects can induce vibration of the void growth rate at the rise stage of loading history and impede the growth at the steady stage. In addition, to study the void growth at the early stage of a void-dominated fracture process, quasistatic cases without inertial effects are examined. It is shown that the void growth rate strongly depends on the evolution of free volume concentration.