A regular thermodynamic model for interstitial iron-carbon solutions

Abstract

A thermodynamic model for the interstitial iron-carbon solution is proposed. The equilibrious thermodynamics properties of carbon in austenite which is predicted by the present model is in full agreement with the experimental data within the temperature range of 900–1400°C. The model can also give a description to the kinetic behavior of the variation in diffusion coefficient of carbon in austenite with the carbon content at various temperatures. Combined with the quasi-regular treatment of carbon atoms in ferrite, the model can further be used to depict accurately the γ (α + γ) and α (α + γ) phase boundaries in the iron-rich region of the FeC phase diagram. What is more, the expressions of thermodynamic functions in the model are simple and explicit, as compared with KRC, LFG and MD models.