Developing alloys with both excellent mechanical properties and oxidation resistance is rather challenging but important for the aerospace industry. In our previous work, we have developed a chemically complex L1₂-strengthened high-entropy alloy (HEA), which exhibits excellent mechanical properties at elevated temperatures. However, its oxidation behavior is still unclear under the effects of multiple principal elements. In the present work, the oxidation behaviors this HEA were studied between 700 and 900 °C in air condition. Despite a relatively high content of Ti, the designed HEA exhibits superior oxidation resistance and unique oxidation mechanisms. The results show that the designed alloy follows a parabolic oxidation film growth dynamic and exhibits low oxidation rates of 4.96 × 10⁻⁶, 3.30 × 10⁻⁴, and 4.42 × 10⁻³ mg²/cm⁻⁴h⁻¹ at 700, 800, and 900 °C, respectively. The superior oxidation resistance can be attributed to the formation of continuous dense multi-oxidation layers, such as Cr₂O₃, Al₂O₃, TiTaO₄, sandwich structure of CoCr₂O₄-Cr₂O₃-CoCr₂O₄ etc. The Ti⁴⁺ ion incorporating into Cr₂O₃ lattice facilitated the formation of protective Cr₂O₃ layer. The formation of TiTaO₄ layer and NiO₂ oxides decreased the oxygen solubility within the interface between the matrix and the transient oxide layer, thus promoted continuous alumina layer formation at high temperature of 900 °C. This work provides valuable guidance for understanding the oxidation behaviors of HEAs with multi-component elements.

中文翻译：

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在化学复杂的 L12 强化高熵合金中具有卓越的抗氧化性和独特的机理

开发具有优异机械性能和抗氧化性的合金相当具有挑战性，但对航空航天工业来说很重要。在我们之前的工作中，我们开发了一种化学复杂的 L1 ₂ 强化高熵合金 （HEA），它在高温下表现出优异的机械性能。然而，在多种主元素的作用下，其氧化行为仍不清楚。在本工作中，研究了这种 HEA 在 700 和 900 °C 之间在空气条件下的氧化行为。尽管 Ti 的含量相对较高，但所设计的 HEA 表现出优异的抗氧化性和独特的氧化机制。结果表明，所设计的合金遵循抛物线氧化膜生长动力学，在 700、800 和 900 °C 下表现出 4.96 × 10 ⁻⁶ 、3.30 × 10 ⁻⁴ 和 4.42 × 10 ⁻³ mg ² /cm ⁻⁴ h ⁻¹ 的低氧化速率。优异的抗氧化性可归因于连续致密多氧化层的形成，如 Cr ₂ O ₃ 、 Al ₂ O ₃ 、 TiTaO ₄ 、 CoCr ₂ O ₄ -Cr ₂ O ₃ -CoCr ₂ O ₄ 的夹层结构等。掺入 Cr ₂ O 晶格的 Ti ⁴⁺ 离子促进了保护性 Cr ₂ O ₃ 层的 ₃ 形成。TiTaO ₄ 层和 NiO ₂ 氧化物的形成降低了基体与瞬态氧化物层界面内的氧溶解度，从而促进了 900 °C 高温下连续氧化铝层的形成。 这项工作为理解具有多组分元素的 HEAs 的氧化行为提供了有价值的指导。