Influence of the shock-induced alpha-epsilon transition in Fe on its post-shock substructure evolution and mechanical behavior

The effect of shock-prestraining high-purity Fe, above and below the 13 GPa phase transition, on postshock compressive stress-strain behavior and subs tructure evolution is presented. The degree of shock hardening in Fe is hig her for shock strength above the transition than below it. The substructure also displayed more deformation twinning for shocks above the phase transi tion than below. The shock hardening in Fe varied with propagation distance . Modeling shock propagation in Fe revealed that for the geometry used, the transition wave was overtaken and quenched by the rarefaction release expl aining the gradient in shock hardening.