EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

A new model has been extended to predict austenite $\leftrightarrow$ ferrite transformation kinetics for complex thermal cycles with the cementite dissolution on a wide range of Fe-C-Mn steels. For each alloying element, the concentration profile is computed solving a unique diffusion equation (including the 2 phases and the interface). The interface is described assuming linear variation of chemical potentials, saving thus computational time. Interface motion is driven by the minimization of Gibbs energy. The model naturally reproduces the transition between thermodynamic equilibria (Para equilibrium, Local equilibrium with negligible partitioning, Local equilibrium) during heating. The model validity for reverse transformation has been validated on cyclic heat treatment.