The atomic mobility descriptions for Y and O in both α-Y(O) and α-Y₂O₃ were first assessed by means of CALculation of PHAse Diagram approach based on the critically-reviewed diffusivities available in the literature. The diffusion anisotropy in α-Y(O) with hcp structure and the short-circuit diffusion in both α-Y(O) and α-Y₂O₃ were taken into account. Based on the assessed atomic mobilities together with the available thermodynamic descriptions, most of the experimental diffusivities can be reproduced satisfactorily. Afterwards, one-dimensional numerical simulations of oxidation of pure yttrium during the initial stage at different temperatures were performed based on a home-made code. The simulated weight gain data of α-Y(O) at different temperatures are in good agreement with the experimental ones, further validating the reliability of the presently obtained atomic mobilities in α-Y(O). It was found that the initial-stage oxidation of α-Y at higher temperatures is mainly controlled by only the bulk diffusion, while the lower temperature initial-stage oxidation is controlled by bulk and short-circuit diffusion simultaneously. Furthermore, the contribution of short-circuit diffusion at lower temperatures is dominant, and can be largely enhanced as the grain size in the specimens decreases.

在这两种α-Y（O）和α-Y用于Y和O的原子迁移率的说明₂ ö ₃首先通过基于在文献中获得的临界审查的扩散系数相图的方法的计算装置评估。与hcp结构和在两个α-Y（O）和短路扩散在α-Y（O）的扩散各向异性α-Y ₂ ö ₃被考虑在内。根据评估的原子迁移率以及可用的热力学描述，可以令人满意地再现大多数实验扩散率。然后，基于自制代码对纯钇在不同温度下初始阶段的氧化进行了一维数值模拟。在不同温度下模拟得到的α-Y（O）的增重数据与实验数据吻合良好，进一步验证了目前获得的α-Y（O）原子迁移率的可靠性。发现在较高温度下，α-Y的初始氧化主要受本体扩散控制，而较低温度下的初始氧化受本体和短路扩散同时控制。此外，