First principles impurity diffusion coefficients

We report the prediction of impurity diffusion coefficients entirely from first principles, using density-functional theory (DFT) calculations. From DFT we obtain all microscopic parameters in the pre-factor and activation energy of impurity diffusion coefficients: (i) the correlation factor through a five frequency model, (ii) the impurity jump frequency within the framework of transition state theory and (iii) the free energies of vacancy formation and vacancy-solute binding. Specifically, we calculate the impurity diffusion coefficients of Mg, Si and Cu in dilute face-centered cubic Al alloys. The results show excellent agreement with experimental data. We discuss the factors contributing to the trends in diffusivities of these impurities. Published by Elsevier Ltd. on behalf of Acta Materialia Inc.