Anisotropic Diffusion Behaviour of Al and Zn in HCP Mg: Diffusion Couple Experiment Using Mg Single Crystal

Diffusion couple experiments for Mg-Al and Mg-Zn were carried out with Mg single crystal to determine the anisotropic diffusion coefficients of Al and Zn in hcp Mg at the temperature range between 553 and 693 K. Based on the experimental results, anisotropic diffusion coefficients of Al and Zn were calculated using multiphase diffusion simulations. Al diffusion in hcp Mg is slightly faster than Mg self-diffusion itself, but the diffusion of Zn is slightly slower than Mg self-diffusion. The diffusion coefficients of Al and Zn along the a-axis (basal plane) of hcp Mg is slightly higher (1.1-1.4 times) than those along the c-axis (normal to the basal plane), which is also similar to Mg self-diffusion behaviour.