Phase Transition and Reverse Transition in FeMnNi Alloy

By means of VISAR, the phase transition and reverse phase transition in FeMnNi alloy under different pressures were studied through direct impact and reverse impact experiments. As the difference between shock pressure and phase transition threshold is larger than reverse transition threshold, namely 0p-tn, it may lead to an occurrence of the phase transition in FeMnNi alloy, and produces a multi-wave structure consisting of an elastic wave, a plastic wave and a phase transition wave. Under the release process, the rarefaction wave reflecting by the plastic wave from the free surface induces the complete reverse phase transition , and forms a multi-wave structure comprising a rarefaction wave, a rarefaction shock wave and another rarefaction wave. As p-tn, it may produce a multi-wave structure with phase interface reflection (PIR) wave. During the release process, the rarefaction wave reflecting by the residual phase wave causes the reverse phase transition , and forms a two-wave structure consisting of a rarefaction wave and a rarefaction shock wave.