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

TL;DR

This paper introduces a dislocation-based model to explain the quasi-elastic release phenomenon in shock-loaded aluminum, successfully matching experimental data and revealing dislocation dynamics during deformation.

Contribution

The study presents a novel dislocation-based explanation for quasi-elastic release in aluminum, incorporating dislocation evolution to accurately simulate elastic-plastic response.

Findings

Dislocation immobilization causes smooth yield stress increase leading to quasi-elastic release.

Dislocation generation during plastic release creates a transition point in velocity profiles.

Simulations agree well with experimental velocity, shear strength, and dislocation density data.

Abstract

A novel explanation of the quasielastic 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 poly crystalline 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 demonstrates the accuracy of our simulations. Simulated results indicate that dislocation immobilization during dynamic deformation results in a smooth increase of 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 quasielastic release and the plastic release in the profile.