Re-assessment of diffusion mobilities in the face-centered cubic Cu–Sn alloys

Based on the available thermodynamic information and diffusion coefficient data of the Cu–Sn binary system, the atomic mobilities of Cu and Sn in face-centered cubic (fcc) Cu–Sn alloys have been assessed as a function of temperature and composition in terms of the CALPHAD method using the DICTRA® software package. Optimized mobility parameters are presented. To testify the reliability of the optimized mobility parameters, the composition–distance profiles of the Cu/Cu-7 at.% Sn diffusion couples at different temperatures (923 K, 1023 K and 1053 K) have been measured in the present work by means of electronic probe micro-analysis (EPMA). Comparisons between the calculated and measured diffusion coefficients show that most of the experimental information can be reproduced reasonably. The obtained mobility parameters can also predict satisfactorily composition–distance profiles of the diffusion zone in binary Cu–Sn diffusion couples determined in the present work and reported in published literature.