A multiphase segregation model for multicomponent alloys with a peritectic transformation
Résumé
A multiphase microsegregation model for the solidification of multicomponent alloys that experience a peritectic transformation is developed. It is based on a volume averaging method. Coupling is achieved among the conservation equations for total mass, solute mass and energy. The diffusion in extradendritic and several interdendritic liquid and solid phases, the growth kinetics of the dendritic and peritectic solidifying microstructures, as well as the velocities of the solid/liquid and solid/solid phase interfaces are considered in the model. The model is applied to the dendritic and peritectic solidification of a Fe-C-Cr alloy. Equilibrium between phases at the interface is taken into account and computed using a thermodynamic software. The occurrence of several recalescences due to the growth of the microstructure and the peritectic transformation are predicted and the solidification behaviors near recalescence are evaluated. By adjusting the parameters, the lever rule (LR), Gulliver-Scheil (GS) and partial equilibrium (PE) approximations are retrieved