Analysis of the x-ray diffraction signal for the α-ε transition in shock-compressed iron:: Simulation and experiment

Recent published work has shown that the phase change of shock-compressed iron along the [001] direction does transform to the epsilon [hexagonal close-packed (hcp)] phase similar to the case for static measurements. This article provides an in-depth analysis of the experiment and nonequilibrium molecular dynamics simulations, using x-ray diffraction in both cases to study the crystal structure upon transition. Both simulation and experiment are consistent with a compression and shuffle mechanism responsible for the phase change from body-centered cubic to hcp. Also both show a polycrystalline structure upon the phase transition, due to the four degenerate directions in which the phase change can occur.