A dislocation-based explanation of quasi-elastic release in shock-loaded aluminum

Abstract

A novel explanation of the quasi-elastic release phenomenon in shock-compressed aluminum is presented. A dislocation-based model, taking into account dislocation substructures and evolution, is applied to simulate the elastic–plastic response of both single-crystal and polycrystalline aluminum. The calculated results are in good agreement with experimental results from not only the velocity profiles but also the shear strength and dislocation density, which demonstrate the accuracy of our simulations. Simulated results indicate that dislocation immobilization during dynamic deformation results in a smooth increase in the yield stress, which leads to the quasi-elastic release, while the generation of dislocations caused by the plastic release wave results in the appearance of a transition point between the quasi-elastic release and the plastic release in the profile.