A REGULAR THERMODYNAMIC MODEL FOR INTERSTITIAL IRON-CARBON SOLUTIONS

A thermodynamic model for the interstitial iron-carbon solution is pro posed. The equilibrious thermodynamics properties of carbon in austeni te which is predicted by the present model is in full agreement with t he experimental data within the temperature range of 900-1400-degrees- C. The model can also give a description to the kinetic behavior of th e variation in diffusion coefficient of carbon in austenite with the c arbon content at various temperatures. Combined with the quasi-regular treatment of carbon atoms in ferrite, the model can further be used t o depict accurately the gamma/(alpha + gamma) and alpha/(alpha + gamma ) 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.