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

Abstract

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 (110) planes around the void and grows along the ［110］,［110］ and ［110］,［110］ directions, respectively, and then grow along 〈111〉 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 statictics of pressure-volume tensor and energy distributions, and give a preliminary analysis of the nucleation and growth of phase transformation.