Computational Study of Mobilities and Diffusivities in bcc Ti-Zr and bcc Ti-Mo Alloys

Based on the abundant experimental diffusion data and the thermodynamic parameters in the literature, the atomic mobilities of bcc Ti-Zr and bcc Ti-Mo alloys are critically assessed by means of the CALPHAD technique in this work. Comprehensive comparisons between the calculated and experimentally measured diffusion coefficients are made, where the presently obtained mobility parameters can satisfactorily reproduce most of the experimental data. Moreover, the atomic mobilities derived in the present work are successfully applied to reproduce some measured concentration profiles from diffusion couples in both binary systems and the displacements of Kirkendall makers in the Ti-Mo binary system. It is believed that the proposed atomic mobility parameters contribute to the establishment of a general Ti mobility database, which is useful in designing novel high-temperature Ti alloys.