DEVELOPMENT OF THE Fe–Al ALLOY PHASE EQUILIBRIUM SYSTEM AND THE Fe–Al–C TRIPLE SYSTEM IN THE THERMO-CALC PROGRAM

In this study, the phase diagrams of the Fe–Al binary and Fe–Al–C ternary systems were analyzed using the Thermo-Calc program. Based on Gibbs free energy, enthalpy, and other thermodynamic parameters, the stability of intermetallic phases under various temperature and compositional conditions was investigated. The results indicate that an increase in aluminum concentration raises Gibbs free energy, thereby reducing the likelihood of phase formation. In contrast, increasing temperature decreases Gibbs free energy, making reactions thermodynamically more favorable. The optimal conditions were observed in the temperature range of 1368–1428 K with 41–49 wt% aluminum, where AL2Fe and AL5Fe4 intermetallic phases are stabilized, enhancing the wettability of aluminum coatings on steel surfaces. In the Fe–Al–C system, an increase in carbon content was found to raise Gibbs free energy, leading to weaker adhesion of the aluminum coating. These findings provide important insights for optimizing aluminized steel coatings by identifying the most favorable thermodynamic conditions.