Computational study of atomic mobilities in Al-Zr solid solutions and the growth of ZrAl3 intermetallic phase

Based on the thermodynamic description, experimental diffusion coefficients and empirical relations, the atomic mobilities of Al and Zr in fcc_Al, bcc_Zr and hcp_Zr phases have been optimized. From the comparisons between the calculated and measured diffusion coefficients, it can be seen that most of the experimental data are reproduced well. A good prediction was also made in the composition-distance profile of the diffusion zone in the Zr/Zr-2.8 wt% Al diffusion couple. Introducing the concept of “average interdiffusion coefficient”, the growth of ZrAl3 intermetallic phase with a narrow homogeneity range in Zr/Al diffusion couples was simulated using the obtained atomic mobility parameters. Meanwhile the average interdiffusion coefficients were assessed and their temperature dependence was then established. The difference in the average interdiffusion coefficients of the ZrAl3 phase based on separate experiments was also explained.