Phase transitions in an Fe system containing a bcc/fcc phase boundary: An atomistic study

Using molecular-dynamics simulation and the Meyer-Entel interaction potential, we investigate the energetics and dynamics of the phase transformation in an Fe bicrystal containing a bcc/fcc interface. The interface obeys the Nishiyama-Wassermann orientation relationship. After relaxation we observe the emergence of threading dislocations at the phase boundary growing into the bcc side. We investigate the spontaneous temperature-induced phase transformation in the Fe bicrystal at temperatures of 100 K and 1300 K. Both homogeneous (at the lower temperature) and heterogeneous transformations are observed. The propagation velocity of the phase boundary amounts to 24 m/s at the low temperature; at the higher temperature, it is one order of magnitude larger. The dynamics of the phase transformation and of the propagating interface are discussed and compared to previous results.