Atomic mobilities and interdiffusion coefficients in the bcc Ti-rich Ti-Cr-Hf system

Diffusion properties are associated with various aspects of the materials, therefore, the establishment of a kinetic database is essential for the design and development of alloys. In this study, eight ternary diffusion couples of bcc Ti-Cr-Hf alloy were fabricated and annealed at 1273 K and 1373 K for 25 h and 18 h, respectively. And then, on the basis of experimental composition profiles, reliable thermodynamic and kinetic information, the atomic mobility interaction parameters for Ti-Cr-Hf system were efficiently assessed by integrating the Numerical Inverse method with the novel diffusion models. The reliability and soundness of the evaluated mobility descriptions were confirmed by good agreement between the measured composition distributions/interdiffusion coefficients/diffusion paths and the predicted results. Further investigations were also conducted on other diffusion properties including temperature- and composition-dependent interdiffusivities and the related Arrhenius relationship.