The Mg-Er binary system, as a new lightweight alloy material system with important research value and prospects for development and application, has attracted much attention from researchers in the field of materials science. Studies have shown that the addition of the rare earth element Er can improve the mechanical strength and heat resistance of magnesium alloys. However, the specific mechanism of the interaction between Mg and Er and its effect on the mechanical properties still need to be studied in depth. A combination of microscopic morphology characterization and nanoindentation experiments were employed to investigate the binary diffusion behavior and mechanical properties of the Mg-Er system between 748 K and 823 K in this research. The results indicate that the growth constant of the diffusion layer increases with temperature, with Mg24Er5 exhibiting a higher growth constant than the sum of Mg2Er and MgEr. Notably, the Mg2Er phase has the lowest growth activation energy (127.81 kJ/mol), which suggests that it is formed first during the initial growth stage due to its relatively low energy barrier. Moreover, the interdiffusion coefficient of Mg24Er5 was found to be the highest. By calculating diffusion activation energy, this sequence of formation (Mg2Er→Mg24Er5→MgEr) is in agreement with the trend of growth activation energy. Additionally, nanoindentation experiments and first-principles calculations were utilized to derive the mechanical properties of the Mg-Er binary system. The investigations unveil that Mg2Er boasts the highest hardness and Young’s modulus. These findings have significant implications for understanding the correlation between structure and properties for the Mg-Er alloy system.

中文翻译：

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Mg-Er二元体系的扩散行为和力学性能


Mg-Er二元体系作为一种具有重要研究价值和开发应用前景的新型轻质合金材料体系，备受材料科学领域研究者的关注。研究表明，稀土元素Er的添加可以提高镁合金的机械强度和耐热性。然而，Mg与Er相互作用的具体机制及其对力学性能的影响仍需深入研究。本研究采用微观形貌表征和纳米压痕实验相结合的方法研究了 Mg-Er 体系在 748 K 至 823 K 范围内的二元扩散行为和力学性能。结果表明，扩散层的生长常数随着温度的升高而增加，Mg24Er5 的生长常数高于 Mg2Er 和 MgEr 的总和。值得注意的是，Mg2Er 相具有最低的生长活化能（127.81 kJ/mol），这表明由于其相对较低的能垒，它是在初始生长阶段首先形成的。此外，发现Mg24Er5的相互扩散系数最高。通过计算扩散活化能，该形成顺序（Mg2Er→Mg24Er5→MgEr）与生长活化能的趋势一致。此外，还利用纳米压痕实验和第一原理计算来推导 Mg-Er 二元系统的机械性能。研究表明，Mg2Er 具有最高的硬度和杨氏模量。这些发现对于理解 Mg-Er 合金系统的结构和性能之间的相关性具有重要意义。