Study of nucleation of void-Induced phase transformation under shock compression

Molecular dynamics simulations have been used to study the nucleation and growth of void-induced phase transformation of single crystal Fe under shock-wave loading along the [001] direction and effects of initial temperature on the process. It was found that: 1) phase transformation nucleates firstly on the (110) and (11̄0) planes around the void and grows along the [11̄0], [1̄10] and [110], [1̄1̄0] directions, respectively, and then grow along <1ll> directions of the (110) and (110) planes, and ultimately V shaped grains form; 2) under the same shock compression, grains at initial temperature 300 K are smaller than those at 60 K, and at the same time, many embryos appear around the grains. These phenomena indicate that void-induced phase transformation nucleates and grows along certain directions, and increasing the initial temperature can diversify the action. Finally, we calculate the statistics of pressure-volume tensor and energy distributions, and give a preliminary analysis of the nucleation and growth of phase transformation.