Diffusivities, atomic mobilities, and simulation of ternary eutectic solidification in the Ag-Al-Cu melts

The recently developed Arrhenius formula of the modified Sutherland equation was applied to calculate the self- and impurity diffusivities for liquid pure elements in the Ag-Al-Cu system. Based on all kinds of diffusivities from the literature and the present work together with the reliable thermodynamic description of the liquid phase available in the literature, the atomic mobilities in the Ag-Al-Cu melts were evaluated using the DIffusion-Controlled TRAnsformations (DICTRA) software package. Comprehensive comparisons between the calculated results and the experimentally measured data show that most of the diffusivities from different sources can be well reproduced by the atomic mobilities obtained in the present work. The atomic mobilities were further verified by comparing the model-predicted concentration profiles and the measured ones in two liquid Ag-Al-Cu diffusion couples. Furthermore, on the basis of the established thermodynamic and atomic mobility databases, the univariant and invariant eutectic solidification in ternary Ag-Al-Cu alloys were also successfully simulated using DICTRA with the aid of a newly designed geometry.