Molecular dynamics simulation of the effects of FCC/BCC interfaces on the nucleation and growth of martensite in iron

Abstract

Molecular dynamics simulations have been used to study the effect of fcc/bcc interfaces in the Nishiyama-Wasserman (N-W) orientation relationship on the fcc-to-bcc transformation at 300 K in pure iron. Simulations show the growth of the original bcc phase present in the initial configuration as well as the nucleation and growth of new bcc grains in the original fcc phase. During growth, heterogeneous and homogenous bcc nuclei both pin the propagation of the original bcc/fcc interface. In some locations, neighboring newly-nucleated bcc plates merge into a single bcc grain. The fcc phase transforms to bcc by a predominantly martensitic mechanism.