Model γ-NiCrAl alloys with and without titanium were oxidized for short times up to 32 h at 1000 °C and subsequently characterized by scanning electron microscopy, transmission electron microscopy, and atom probe tomography in order to clarify the role of Ti on the oxidation behavior of alumina-forming nickel alloys. At the longer oxidation times, Ti was found to have no significant effect on the major protective oxide phases formed and overall scale and individual oxide layer thicknesses. Ti was observed to segregate to interfaces within the scale and form a Ti-rich oxide at the scale surface over time. At the shortest oxidation times before a continuous Al2O3 layer formed, the Ti-containing alloys exhibited thicker Cr2O3 layers, suggesting that Ti accelerates Cr2O3 growth kinetics. Additionally, oxide nodules resulting from fast oxidation of TiN particles were observed on the Ti-containing alloys. These may be linked to increased spalling propensity of Ti-containing alloys.Graphical Abstract

中文翻译：

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Ti对形成氧化铝的NiCrAl合金氧化早期阶段的影响

将含钛和不含钛的模型 γ-NiCrAl 合金在 1000 °C 下进行长达 32 小时的短时间氧化，然后通过扫描电子显微镜、透射电子显微镜和原子探针断层扫描进行表征，以阐明 Ti 对氧化行为的作用形成氧化铝的镍合金。在较长的氧化时间下，发现 Ti 对形成的主要保护性氧化物相以及整体氧化皮和单个氧化物层厚度没有显着影响。观察到 Ti 偏析到氧化皮内的界面，并随着时间的推移在氧化皮表面形成富钛氧化物。在形成连续 Al2O3 层之前的最短氧化时间下，含 Ti 合金表现出较厚的 Cr2O3 层，表明 Ti 加速了 Cr2O3 的生长动力学。此外，在含钛合金上观察到由 TiN 颗粒快速氧化产生的氧化物结节。这些可能与含钛合金剥落倾向增加有关。 图形摘要