The effects of crystal orientation on the β to γ transition in tin under shock loading*

The asymmetry of the crystal lattice of tin provides a challenge to modelling of phase transitions. The beta-gamma phase transition is particularly important, given the relatively low pressure required to reach the transition. While the transition has been well mapped, and the hysteresis of the transition under shock demonstrated, little consideration has been made on the role crystal orientation plays in the transition. To better understand this transition, gas-gun plate-impact experiments are being conducted on tin, to measure the onset of transition for the various crystal orientations under shock. These experiments subject tin to shock states just over the transition threshold to generate a split wave, detectable by PDV, from which the transition properties can be derived. Multiple probes of PDV are used in an optical relay to quantify the tilt of the shock wave, which is essential for understanding the dynamics of single crystals. Ultimately, this research aims to help quantify the role crystal orientation plays in the phase transition, and thereby provide an opportunity to validate and challenge atomistic models of materials behaviour. UK Ministry of Defence © Crown Owned Copyright 2023/AWE.