Abstract Spark plasma sintering (SPS) enables the manufacturing of TiAl alloys with an exceptional combination of low density and mechanical properties such as acceptable ductility at room temperature and high strength at high temperature. However, TiAl alloys are known to exhibit low oxidation resistance above 700 °C. The oxidation of a Ti–48Al–2W–0.1B (at. %) processed by SPS was investigated at 800 °C. Coupons were oxidized in air and in Ar-21O 2 (vol%), in isothermal and cyclic tests. In air, the alloy formed a mixture of Ti and Al oxides, but oxidation was slower than typically observed for W-free alloys. The oxide scale and underlying alloy were characterized by X-ray diffraction and electron microscopy in order to examine the beneficial role of W in the oxidation resistance. The main constituents of the reaction product after reaction in air may be described as follows (from gas to alloy): TiO 2 /porous Al 2 O 3 /TiO 2 + Al 2 O 3 /TiN + Al 2 O 3 + W/TiAl 2 + W/TiAl. Close examination suggests that the relatively good oxidation resistance of the alloy is related to W doping of TiO 2 in the mixed Al 2 O 3 + TiO 2 layer. The alloy formed an Al-rich oxide scale with much slower kinetics in Ar-21O 2 , confirming the detrimental role of N in the oxidation process. Graphic Abstract

中文翻译：

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火花等离子烧结 Ti–48Al–2W–0.1B 合金在 800 °C 时的氧化行为

摘要 放电等离子烧结 (SPS) 能够制造出兼具低密度和机械性能的 TiAl 合金，例如室温下可接受的延展性和高温下的高强度。然而，已知 TiAl 合金在 700 °C 以上表现出低抗氧化性。在 800 °C 下研究了由 SPS 处理的 Ti-48Al-2W-0.1B（原子百分比）的氧化。在等温和循环测试中，试样在空气和 Ar-21O 2 (vol%) 中被氧化。在空气中，该合金形成了 Ti 和 Al 氧化物的混合物，但氧化速度比通常观察到的无 W 合金要慢。氧化皮和下面的合金通过 X 射线衍射和电子显微镜进行表征，以检查 W 在抗氧化性中的有益作用。在空气中反应后反应产物的主要成分可描述如下（从气体到合金）： TiO 2 /多孔Al 2 O 3 /TiO 2 + Al 2 O 3 /TiN + Al 2 O 3 + W/TiAl 2 + W/TiAl。仔细检查表明，合金相对较好的抗氧化性与混合Al 2 O 3 + TiO 2 层中TiO 2 的W掺杂有关。该合金在 Ar-21O 2 中形成了具有慢得多的动力学的富铝氧化皮，证实了 N 在氧化过程中的不利作用。图形摘要 该合金在 Ar-21O 2 中形成了具有慢得多的动力学的富铝氧化皮，证实了 N 在氧化过程中的不利作用。图形摘要 该合金在 Ar-21O 2 中形成了具有慢得多的动力学的富铝氧化皮，证实了 N 在氧化过程中的不利作用。图形摘要