Abstract: A thermodynamic analysis on in-situ TiC synthesis in Fe-C-Ti-Mn system was made on the basis of solution thermodynamics theory. Calculated results show that the formation of TiC is ahead of the formation of Fe₃C and Fe₂Ti and TiC is more stable than Fe₃C and Fe₂Ti thermodynamically. Usually, TiC is formed before the solidification of matrix alloy while Fe₃C and Fe₂Ti are separated during the solidification and cooling process of the alloy. With the increase of C concentration, the possibility of TiC and Fe₃C formation are increased.Furthermore,with higher Ti concentration, the possibility of Fe₂Ti and Fe₃C formation are increased and decreased, respectively. The formation of TiC is promoted when the concentration of C and Ti are higher and that of Fe₂Ti is promoted when Ti concentration is higher and C concentration is lower.Moreover, the formation of Fe₃C is prompted when C concentration is higher and Ti concentration is lower.By addition of appropriate amount of Mn, the formation of Fe₃C is inhibited effectively and the TiC synthesis temperature reduces significantly,so that most of TiC synthesis reaction will take place in the alloy solidification and cooling process after the molten alloy fills up the cast form,thus it is possible to solve the problem of too early separation of TiC and form filling difficulty due to increase of molten alloy viscosity.

Key words: Fe-C-Ti-Mn system, TiC particle, in-situ synthesis, thermodynamics