Thermodynamic assessment of the Co-Cr-Fe system and atomic mobility study of its fcc phase

In the present work, the Co-Cr-Fe system was thermodynamically assessed by using the CALPHAD approach coupled with first-principles calculations and experimental data from the literature. Subsequently, the fcc Co-Cr-Fe ternary diffusion couples annealed at 1273 and 1473K were scanned by using electron probe micro-analysis (EPMA) to obtain the composition profiles, from which the interdiffusion coefficients were extracted by the Whittle-Green method. Based on these interdiffusion coefficients and present thermodynamic parameters, the atomic mobilities of Co, Cr, and Fe in the fcc Co-Cr-Fe alloys were assessed by means of DICTRA software. The calculated interdiffusion coefficients, composition profiles and diffusion paths of the fcc Co-Cr-Fe alloys were consistent with the experimental data, which verifies the accuracy of the assessed atomic mobilities.