Revised thermodynamic description of the Fe-Cr system based on an improved sublattice model of the σ phase

The Fe-Cr system is re-assessed, focusing on an improved modeling of σ phase. The three sublattice model (Cr,Fe)10(Cr,Fe)4(Cr,Fe)16 is parameterized to model the σ phase, solving discrepancies between computed and experimental site fractions of previous descriptions. Taking into account relative metastability trends of end-member compounds from first-principles analysis, only two additional interaction parameters of the σ-FeCr description were required for the reproduction of the chemical structure, thermodynamic properties and phase boundaries.