Abstract Short-term isothermal oxidation of TiAl 48-2-2 alloy produced by Electron Beam (EBM) was investigated at 750, 800, 850 and 900 °C with special focus on the oxidation kinetics and metal-scale interface evolution. It was shown that at the lowest oxidizing temperature a passivating and thin mixture of alumina and titania is formed with subsurface Z-phase formation. At higher temperatures a porous and non-protective oxide scales formed with subsequent nitridation at the metal-scale interface. Moreover, long-term isothermal oxidation at 750 °C up to 3000 h in 500 h intervals was performed and related to the initial band microstructure of the alloy resulting from EBM process. Internal oxidation was observed on lamellar α2 / γ colonies while α-alumina mixed with TiN and Ti2AlN was found to form on equiaxed γ-TiAl regions. Analytical Scanning Electron Microscopy (STEM) aided with Energy Dispersive Spectroscopy (EDS) and Electron Energy Loss Spectroscopy (EELS) were used for investigations of the oxide scales as well as nitride layers formation at different temperatures.

中文翻译：

---

等温氧化后增材制造生产的 γ-TiAl 的 STEM 研究

摘要 研究了电子束 (EBM) 生产的 TiAl 48-2-2 合金在 750、800、850 和 900 °C 下的短期等温氧化，特别关注氧化动力学和金属尺度界面演化。结果表明，在最低氧化温度下，会形成氧化铝和二氧化钛的钝化和稀薄混合物，并在表面下形成 Z 相。在更高的温度下，多孔和非保护性氧化皮形成，随后在金属鳞片界面处进行氮化。此外，在 750 °C 下以 500 小时为间隔进行长达 3000 小时的长期等温氧化，这与 EBM 工艺产生的合金的初始带状微观结构有关。在层状α2 / γ 菌落上观察到内部氧化，而在等轴γ-TiAl 区域上发现与TiN 和Ti2AlN 混合的α-氧化铝。