Diffusion behaviors in Mg–Sc hcp and bcc solid solutions between 773 and 873 K were investigated using both single-phase and multi-phase diffusion couple techniques. The EPMA detected composition-distance profiles were smoothed and fitted using the error function expansion (ERFEX). The interdiffusion coefficients were extracted using Sauer–Freise integral. The interdiffusion coefficients in hcp phase showed a slightly parabolic composition dependence at the Mg-rich part and the maximum value was around 2–3 at. % Sc. However, the interdiffusion coefficients in the bcc phase monotonously decreased with the increase of solubility of Sc. The determined inter- and impurity diffusion coefficients in the hcp Mg–Sc alloys were assessed to develop the atomic mobility database, and their validity was justified by reproducing the composition profiles and diffusion fluxes obtained in this diffusion couple experiment. Meanwhile, the development of bcc atomic mobility was realized via the Maclaurin approximation, extrapolation, and optimization. The results make up for the missing data of Mg–Sc diffusion kinetics.

使用单相和多相扩散耦合技术研究了Mg-Sc hcp和bcc固溶体在773和873 K之间的扩散行为。使用误差函数扩展（ERFEX）对EPMA检测到的成分距离分布进行平滑和拟合。使用Sauer-Freise积分提取互扩散系数。hcp相的互扩散系数在富含Mg的部分显示出略微抛物线的成分依赖性，最大值约为2–3 at。％Sc 但是，随着Sc的溶解度增加，bcc相中的互扩散系数单调降低。对确定的六方晶系Mg-Sc合金中的杂质扩散系数和杂质扩散系数进行评估，以开发原子迁移率数据库，并通过再现在该扩散偶实验中获得的成分分布和扩散通量证明了其有效性。同时，通过Maclaurin逼近，外推和优化实现了bcc原子迁移率的发展。结果弥补了Mg-Sc扩散动力学的缺失数据。