Thermodynamic Evaluation of the Fe-Zn Binary System with Reference to the Latest Experimental Phase Diagram

The phase diagram of the Fe-Zn binary system was evaluated based on the CALPHAD method with reference to the latest experimental data. The solubility ranges of the intermetallic compound phases, Γ-Fe₄Zn₉, Γ₁-Fe₁₁Zn₄₀, δ_1k-FeZn₇, δ_1p- Fe₁₃Zn₁₂₆, and ζ-FeZn₁₃ were modeled considering their structures consisting of Zn₁₂ icosahedra with Fe at the center (Fe₁Zn₁₂ clusters) as well as glue-like Fe and Zn atoms, and the miscibility gap between the δ_1k and δ_1p phases was also taken into account in the present calculations. The solubility of Fe in the liquid and (ηZn) phases that was confirmed as dozens of times larger than the values reported in the earlier literature could be calculated by introducing Fe₁Zn₁₂ associates to these solution phases. Consequently, all phase equilibria were adequately reproduced by the thermodynamic models and parameters revised in the present study.