On the ultra-high-strain rate shock deformation in copper single crystals: multiscale dislocation dynamics simulations

Multiscale dislocation dynamics plasticity (MDDP) calculations are carried out to simulate the mechanical response of copper single crystals that have undergone shock loading at high strain rates ranging from 1?×?10⁶ to 1?×?10¹⁰?s^?1. Plasticity mechanisms associated with both the activation of pre-existing dislocation sources and homogeneous nucleation of glide loops are considered. Our results show that there is a threshold strain rate of 10⁸?s^?1 at which the deformation mechanism changes from source activation to homogeneous nucleation. It is also illustrated that the pressure dependence on strain rate follows a one-fourth power law up to 10⁸?s^?1 beyond which the relationship assumes a one-half power law. The MDDP computations are in good agreement with recent experimental findings and compare well with the predictions of several dislocation-based continuum models.