Diffusivities and atomic mobilities in fcc Pt-Al alloys

Based on the first-principles computed activation energy, the frequency prefactor for impurity diffusivity of Pt in fcc Al was calculated by means of the Swalin correlation. The Vignes-Birchenall correlation originally developed for binary solutions with unlimited solubility was simplified to evaluate the interdiffusivities in binary terminal solutions with limited solubility. The simplified correlation was validated in fcc Ni-Al alloys, and then applied to evaluate interdiffusivities in fcc Pt-Al alloys, showing a reasonable agreement with the limited experimental data. On the basis of the limited experimental diffusivities in the literature and the presently evaluated interdiffusivities, a set of reasonable atomic mobilities in fcc Pt-Al alloys was established. This combinational approach by utilizing the limited experimental data, first-principles results, semi-empirical/empirical correlations and DIffusion Controlled TRAnsformation (DICTRA) software package is of general validity and applicable in other binary alloys with limited diffusivity information.