The present study investigated the sintering behaviour of Nb–16Si–25Ti–8Hf–2Cr–2Al alloy powders. The alloy powders were produced using ahydrogenation–dehydrogenation method and featured an irregular morphology. Powders sintered at 1500°C and 1600°C exhibited pores in their microstructures, while powders sintered at 1700°C for 4 h were fully densified and poreless. The cast ingot and powders were composed of three phases: Nbss, Nb5Si3, and Nb3Si. However, the Nb3Si phase was not observed, while HfO2 oxides formed in the sintered compact. The hafnium and oxygen reacted to form an HfO2 oxide during the high-temperature sintering process. From the result of the thermodynamic calculation, Hf oxide formed after sintering because Hf has the highest driving force for oxidation among the elements constituting the alloy.

中文翻译：

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加氢-脱氢法制备的Nb-16Si-25Ti-8Hf-2Cr-2Al合金粉末的烧结行为

本研究调查了 Nb-16Si-25Ti-8Hf-2Cr-2Al 合金粉末的烧结行为。合金粉末采用加氢-脱氢方法生产，具有不规则的形貌。在 1500°C 和 1600°C 下烧结的粉末在其微观结构中显示出孔隙，而在 1700°C 下烧结 4 小时的粉末完全致密且无孔。铸锭和粉末由三相组成：Nbss、Nb5Si3 和 Nb3Si。然而，没有观察到 Nb3Si 相，而在烧结体中形成了 HfO2 氧化物。在高温烧结过程中，铪和氧反应形成 HfO2 氧化物。从热力学计算结果来看，Hf 氧化物在烧结后形成，因为 Hf 在构成合金的元素中具有最高的氧化驱动力。