Abstract Refractory complex concentrated alloys (RCCAs) represent an emerging class of materials that have displayed significant potential for increased mechanical performance at extreme temperatures over conventional refractory alloys and Ni-base superalloys. While limited work has been conducted in this area, several RCCAs have shown remarkable levels of oxidation resistance in comparison to the majority of uncoated commercial refractory alloys. However, the oxidation mechanisms in these types of alloys have not been well understood. This study aims to develop the foundation for understanding RCCA oxidation mechanisms through the systematic evaluation of NbTiZrV and NbTiZrCr, which display vastly different oxidation behaviors. In both cases, the predominant mechanism appeared to be internal oxidation, where a mixture of simple and complex oxides was observed after prolonged oxidation times. This resulted in extended linear oxidation kinetics for the NbTiZrV alloy and linear to near-parabolic oxidation kinetics for the NbTiZrCr alloy. Under this mindset, novel design strategies for promoting increased oxidation resistance in both RCCAs and dilute refractory alloys based on sluggish complex oxides are proposed.

中文翻译：

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等摩尔 NbTiZrV 和 NbTiZrCr 难熔复合浓缩合金 (RCCA) 的高温氧化行为

摘要 难熔复合浓缩合金 (RCCA) 代表了一类新兴材料，与传统的难熔合金和镍基高温合金相比，在极端温度下具有显着提高机械性能的潜力。虽然在该领域开展的工作有限，但与大多数未涂层的商业耐火合金相比，一些 RCCA 已显示出显着的抗氧化水平。然而，这些类型合金的氧化机制尚未被很好地理解。本研究旨在通过系统评估 NbTiZrV 和 NbTiZrCr 的氧化行为，为了解 RCCA 氧化机制奠定基础。在这两种情况下，主要的机制似乎是内部氧化，在延长氧化时间后观察到简单和复杂氧化物的混合物。这导致 NbTiZrV 合金的线性氧化动力学延长，NbTiZrCr 合金的线性氧化动力学接近抛物线。在这种心态下，提出了新的设计策略，以提高 RCCA 和基于惰性复合氧化物的稀难熔合金的抗氧化性。