The propagation of shock waves through polycrystalline iron is explored by large-scale
atomistic simulations. For large enough shock strengths the passage of the wave causes the
body-centered-cubic phase to transform into a close-packed phase with most structure being
isotropic hexagonal-close-packed (hcp) and, depending on shock strength and grain
orientation, some fraction of face-centered-cubic (fcc) structure. The simulated shock
Hugoniot is compared to experiments. By calculating the extended x-ray absorption fine …

At a pressure of around 13 GPa iron undergoes a structural phase transition from the bcc to
the hexagonal close-packed phase. Atomistic simulations have provided important insights
into this transition. However, while experiments in polycrystals show clear evidence that the
α-ε transition is preceded by plasticity, simulations up to now could not detect any plastic
activity occurring before the phase change. Here we study shock waves in polycrystalline Fe
using an interatomic potential which incorporates the α-ε transition faithfully. Our simulations …