Carbon diffusion during deformation induced ferrite transformation in a low carbon steel

In order to investigate the carbon diffusion during the deformation induced ferrite transformation, the electron probe microanalysis technique was used to measure the carbon concentration distribution in the microstructure of the specimen which experienced a hot compression process on the thermomechanical simulator (Gleeble 1500). The measurement results indicated that the carbon concentration was significantly supersaturated in the deformation induced ferrite grains, which means that there was no carbon atoms diffusion from the ferrite to the austenite during the deformation induced ferrite transformation. According to the thermodynamics analysis, there is no need for the carbon atoms to diffuse from the ferrite to the austenite during the transformation, because the accumulated stored energy has become the unique driving force when the deformation temperature is higher than the austenite-ferrite equilibrium transformation temperature A_e3.