Numerical Modeling of Growth Kinetics of Pro-eutectoid Ferrite Transformed from Austenite in Fe-C-Σ X Alloys

In the present paper, a numerical modeling was developed to simulate the growth kinetics of ferrite transformed fromaustenite in Fe-c-Σ X (X denotes substitution elements, such as Mn, Ni, Cr etc.) steels by solving the diffusionequation using finite difference method (FDM). Coupled with the kinetic modeling, thermodynamic calculations werecarried out to determine the γ/α phase equilibrium conditions using a para-equilibrium (PE) model. The dissipation offree energy for phase transformation due to the so-called solute drag effect (SDE) was taken into account in thethermodynamic modeling. With this modeling, simulations on the growth kinetics of ferrite in the steels containingaustenite-stabilizing and ferrite-stabilizing elements (such as Ni, Mn and Si, Cr, respectively) were performed, whichindicates that it deviates from the parabolic growth rate law after the initial stage of transformation. The results werecompared with the experimental values given by Bradley and Aaronson, showing that this model has a reasonablygood accuracy to predict the growth kinetics of ferrite.