Measurement of the diffusion coefficient in Mg–Sn and Mg–Sc binary alloys

Abstract

Diffusion coefficients in the hexagonal close-packed (hcp) Mg–Sn and Mg–Sc solid solutions and the body-centered cubic (bcc) Mg–Sc solid solution were re-evaluated via a method combing diffusion couple experiments, error function expansion fitting, and Sauer–Freise/Hall numerical calculation. The interdiffusion coefficients in hcp Mg–Sn alloys were found to gently rise as the content of Sn increases. The new experimental data amended the compositional dependency of Mg–Sn interdiffusion coefficients and gave rise to a new set of mobility parameters. The interdiffusion coefficients in Mg–Sc alloys were determined at 773 K, 803 K, and 848 K. They showed a slightly parabolic composition dependence in the hcp phase but a monotonic decreasing trend with the increase in Sc content in the bcc phase. The experimental results in this work enriched the determined diffusion coefficients in Mg alloys and effectively justified the assessed mobility parameters in assessments.