Thermodynamic and kinetic assessments in Co-Cr-Mn system using diffusion data

Atomic mobility and thermodynamic assessments of the fcc Co-Cr-Mn system were performed using the ternary diffusion data. Diffusion couples in the Co-rich region of the ternary fcc Co-Cr-Mn system were prepared and annealed at 900, 1050, and 1150 degrees C. The concentration profiles across the joint interface were measured using an electron probe microstructure analysis technique. The interdiffusivities were evaluated using the Whittle-Green method, and the atomic mobility parameters of the fcc phase were evaluated via numerical analysis of the diffusional flux. The thermodynamic parameters of the binary fcc Cr-Mn alloy were also determined using the CALPHAD method during the assessment of the mobility parameters in the Co-Cr-Mn system. The atomic mobility and thermodynamic descriptions obtained in this study were used to simulate the ternary concentration profiles. The excellent agreement between the experimental and simulated diffusion data validates the atomic mobility and thermodynamic parameters evaluated in this study.