Abstract MoSi2 is an important intermetallic with excellent oxidation resistance at high temperatures above 1000 °C. However, its application at lower temperatures is limited by oxygen embrittlement, a phenomenon known as “pesting”. In this work, we comprehensively investigate the role of Zr in mitigating pesting in MoSi2 using density functional theory calculations. We show that Zr dopants reduce the embrittling effects of oxygen interstitials at MoSi2 grain boundaries by being a charge donor to oxygen. However, a more substantial effect is observed when Zr is present as a secondary getter nanoparticle phase. Oxygen interstitials have a strong thermodynamic driving force to migrate into the Zr subsurface at the Zr/MoSi2 interface, and the work of separation of the clean and oxygen-contaminated Zr/MoSi2 interfaces are much higher than that of MoSi2 grain boundaries. Finally, we present an efficient screening approach to identify other potential getter elements using simple thermodynamic descriptors, which can be extended to other alloy systems of interest. These findings provide crucial fundamental insights and further avenues to optimize Mo and other alloys.

中文翻译：

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根据密度泛函理论计算，Zr 在强化 MoSi 2 中的作用

摘要 MoSi2 是一种重要的金属间化合物，在 1000 °C 以上的高温下具有优异的抗氧化性。然而，它在较低温度下的应用受到氧脆的限制，这种现象被称为“虫害”。在这项工作中，我们使用密度泛函理论计算全面研究了 Zr 在减轻 MoSi2 中的虫害方面的作用。我们表明，Zr 掺杂剂通过成为氧的电荷供体来降低 MoSi2 晶界处氧间隙的脆化效应。然而，当 Zr 作为二次吸气剂纳米颗粒相存在时，观察到更显着的影响。氧间隙具有很强的热力学驱动力，可以在 Zr/MoSi2 界面处迁移到 Zr 地下，清洁的和被氧污染的 Zr/MoSi2 界面的分离工作远高于 MoSi2 晶界。最后，我们提出了一种使用简单的热力学描述符来识别其他潜在吸气剂元素的有效筛选方法，该方法可以扩展到其他感兴趣的合金系统。这些发现为优化 Mo 和其他合金提供了重要的基本见解和进一步的途径。