Interdiffusion and atomic mobility in bcc Ti-rich Ti-Nb-Zr system

Accurate interdiffusion information is the necessity for the control of the production of homogeneous biomedical alloys. Ternary interdiffusivities in bcc Ti-rich Ti-Nb-Zr alloys at 1273 K were determined by using the combination of the diffusion couple technique and the Matano-Kirkaldy method. Subsequently, on the basis of the presently obtained interdiffusivities together with the diffusivity and mobility parameters of sub-binary Ti-Nb-Zr system and the thermodynamic descriptions for bcc Ti-Nb-Zr system, the atomic mobilities of Ti, Nb and Zr in bcc Ti-Nb-Zr alloys were assessed by means of DICTRA (DIffusion Controlled TRAnsformation) software package. Moreover, the comprehensive comparisons between the experimental diffusion properties (i.e., interdiffusivities, composition profiles, interdiffusion fluxes and diffusion paths) and the calculated/model-predicted data due to the present atomic mobilities were conducted in order to verify the reliability of the mobilities. The present atomic mobilities for bcc Ti-Nb-Zr system can provide the accurate interdiffusivity matrix over the wide composition range.