Greta Lindwall, Kil-Won Moon, Zhangqi Chen, Michael J. Mengason, Maureen E. Williams, Justin M. Gorham, Ji-Cheng Zhao, Carelyn E. Campbell
Diffusion in the Ti-Al-V system is studied and a CΑLPHAD diffusion mobility description is developed. Diffusion couple experiments are used to obtain information of Al and V diffusion in the α phase. This includes diffusion paths at the temperatures 923 K, 1023 K and 1123 K. It can be concluded that the diffusion coefficient of V in the α-Ti phase decreases with increasing Al alloying. The forward-simulation method is used to evaluate the impurity diffusion coefficient for Al and V diffusion in the α Ti-V and the Ti-Al systems which are used as input in the mobility modeling. The composition dependency for the diffusion in the α-phase in the ternary system is accounted for and a CALPHAD diffusion mobility description is obtained by directly optimizing the mobility parameters as a function of the experimental composition profiles from the diffusion couples. Literature data in terms of experimental data and previous diffusion mobility descriptions for diffusion in the β Ti-Al-V are adopted for the diffusion in the β-phase. A complete description of diffusion in α and β phases for the Ti-Al-V system is presented with the aim to be used for design of Ti alloys and processes.