TiAl-based alloys containing relatively high Mn (e.g., Ti–42Al–5Mn (in at.%)) possess excellent hot workability and cost-effective advantages, but may also have poor oxidation resistance at high temperature. Hence, additional attention needs to be paid on the oxidation resistance of these alloys. In this study, a Mn-containing γ-TiAl-based alloy with the composition of Ti–42Al–5Mn has been chosen, and the oxidation behavior of this alloy with different W additions under thermal cycling conditions at 800 °C was investigated. The morphology and the composition distribution of the oxide scale were analyzed by means of scanning electron microscopy equipped with energy-dispersive spectroscopy, X-ray diffractometry and X-ray photoelectron spectroscopy. Auger electron spectroscopy depth profiling was used to investigate the effect of W on the initial stage of oxidation. It shows that the addition of 1 (at.%) W can significantly reduce the oxidation mass gain, and the oxidation reaction rate constant is decreased by an order of magnitude. The adherence of oxide scale is greatly enhanced with no spallation observed in Ti–42Al–5Mn–(0.8, 1)W after 100-h cyclic oxidation. Tungsten promotes the selective oxidation of Al and formation of a denser oxide scale which prevents the inward diffusion of oxygen; in this way, high-temperature oxidation resistance of the alloy is improved.

中文翻译：

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添加 W 的含 Mn β-Gamma TiAl 的高温氧化性能改进

含有相对较高 Mn 的 TiAl 基合金（例如，Ti-42Al-5Mn（以原子百分比计））具有出色的热加工性和成本效益优势，但也可能在高温下具有较差的抗氧化性。因此，需要额外注意这些合金的抗氧化性。在本研究中，选择了成分为 Ti-42Al-5Mn 的含 Mn γ-TiAl 基合金，并研究了该合金在 800 °C 热循环条件下添加不同 W 时的氧化行为。通过配备能量色散谱、X射线衍射和X射线光电子能谱的扫描电子显微镜分析氧化皮的形貌和组成分布。俄歇电子能谱深度分析用于研究 W 对氧化初始阶段的影响。表明加入1(at.%)W可以显着降低氧化质量增加，氧化反应速率常数降低一个数量级。在 100 小时循环氧化后，Ti-42Al-5Mn-(0.8, 1)W 中没有观察到剥落，氧化皮的附着力大大增强。钨促进铝的选择性氧化并形成更致密的氧化皮，防止氧向内扩散；这样就提高了合金的高温抗氧化性。在 100 小时循环氧化后，Ti-42Al-5Mn-(0.8, 1)W 中没有观察到剥落，氧化皮的附着力大大增强。钨促进铝的选择性氧化并形成更致密的氧化皮，防止氧向内扩散；这样就提高了合金的高温抗氧化性。在 100 小时循环氧化后，Ti-42Al-5Mn-(0.8, 1)W 中没有观察到剥落，氧化皮的附着力大大增强。钨促进铝的选择性氧化并形成更致密的氧化皮，防止氧向内扩散；这样就提高了合金的高温抗氧化性。