C-C INTERACTION ENERGY IN Fe-C ALLOYS

A new approach has been suggested for the determination of the C-C interaction energy, the partial molar enthalpy and nonconfigurational entropy of carbon in the Fe-C austenite and ferrite from available activity data. By application of the values obtained through the approach to the calculation of the Fe-C phase diagram, the results in the equilibrium region are in very good agreement with the experimental one. From the scattered and limited experimental activity data, the C-C interaction energy obtained through the present approach should be more reasonable than that through previous efforts. Further analysis indicates, however, that up to now the activity data on carbon in ferrite are not accurate enough for obtaining the C-C interaction energy in ferrite with the clear physical significance.