Simulation of the kinetics of precipitation reactions in ferritic steels

Computer simulations of diffusion-controlled phase transformations in model alloys of Fe-Cr-C, Fe-Cr-W-C, Fe-Cr-Si-C, and Fe-Cr-Co-V-C are presented. The compositions considered are typical for ferritic steels. The simulations are performed using the software DICTRA and the thermodynamic calculations of phase equilibria are performed using Thermo-Calc. The thermodynamic driving forces and the kinetics of diffusion-controlled precipitation reactions of M{sub 23}C{sub 6}, M{sub 7}C{sub 3}, cementite and Laves-phase (Fe, Cr){sub 2}W are discussed. The simultaneous growth of stable and metastable phases is treated in a multi-cell approach. The results show remarkable effects on the growth kinetics due to the competition during simultaneous growth.