Molecular-dynamics study of the α ↔ γ phase transition in Fe-C

Using molecular dynamics simulation, we study the austenitic and the martensitic solid-solid phase transformation in the Fe-C system. Random alloys with C contents up to 1 at% are subjected to a heating/cooling cycle. The martensite and austenite phase transition temperatures can be determined from the hysteresis of the system volume with temperature. The martensite temperature decreases with C content, as in experiment. The influence of the C atom position on the phase transformation and the pathways of the transition are analyzed. The transformed austenite phase shows strong twinning.