Phase field simulations of the peritectic solidification of Fe-C

The microstructure evolution during the peritectic solidification of Fe-C is simulated using a multiphase field approach. The peritectic transformation in steel is a diffusion controlled non-equilibrium process with the three phases liquid, ferrite and austenite involved. Phase fields are defined for each of the three phases. A set of phase field equations is derived from a free energy formulation, whereas the carbon diffusion equation is derived separately by a solute diffusion model. Both phase field and solute diffusion model as well as their coupling will be discussed. Simulation results will be presented showing the growth of the primary ferrite and the subsequent peritectic transformation, in which the austenitic phase is formed.