Influence of quartz anisotropy on shock propagation and spall damage

Stress wave propagation and shock-induced damage in quartz are issues of key interest for many applications. Here, we present original observations in laser shock-loaded single-crystal quartz, showing the strong influence on spall damage of the direction of shock application versus crystal orientation. Indeed, due to the anisotropy of the quartz atomic structure, a compressive pulse applied onto a circular spot may propagate in an oblique direction, or change shape during its propagation through the target, so that its reflection on the opposite free surface may produce specific damage, in unexpected locations. Such anisotropic effects have been investigated experimentally by applying laser shocks on thick samples of single-crystal quartz along the three particular crystallographic axis. Preliminary three-dimensional computer simulations based on the rigidity matrix of quartz have confirmed those effects, and a good overall consistency has been obtained between observed and computed damage in all three cases.