Determination of interdiffusion coefficients in single crystal superalloys based on solute distribution at the dendritic scale using the Gaussian solution model.

Since the initial solute concentration distribution of the sinusoidal solution model shows a significant deviation from the actual concentration distribution of nickel-based single crystal (SX) superalloy dendrites, it is limited to calculate the diffusion coefficient of SX in the homogenization treatment. Therefore, this work proposes a new Gaussian solution model to calculate the diffusion coefficients and the diffusion activation energy of alloying elements in SX superalloy at high temperatures. The diffusion activation energies of W, Ta, and Ti elements in the studied alloy are consistent with the results from other works. This model could more accurately determine the diffusion coefficient of elements during the dendrite homogenization process of SX superalloys since it reflects actual physical processes. Moreover, it has the potential to use in various alloy systems and contributes to the formulation of effective homogenization treatments. • A new model is proposed to accurately determine the inter diffusion coefficient of single-crystal superalloys. • The model shows that a higher gradient of the diffusion chemical potential results in a higher final diffusion coefficient. • The results of the diffusion activation energy demonstrate the robustness of this model. [ABSTRACT FROM AUTHOR]