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研究了不同Cr、Ti、Ta含量定向凝固Ni基高温合金的1223 K恒温氧化行为。结果表明:Cr、Ti、Ta对合金的抗氧化性能在氧化的不同阶段作用各异。在氧化初期,由于Ti元素与O的亲和力很强,Ti含量高的No.3合金在氧化曲线上增重较为明显,而随着氧化的进行,Cr含量高的No.1合金增重较大,这是由于Cr的选择性氧化所致。在1223 K,No.1合金中Ti和Ta含量较低无法形成有效弥散分布于Cr2O3之中,难以形成连续的保护性氧化膜,从而不能有效地阻碍Cr3+向合金内部持续扩散。而No.2和No.3合金中Ti和Ta含量适中,形成连续膜可延缓Cr3+的持续向外扩散,对改善合金的抗氧化能力有积极作用。
The 1223 K isothermal oxidation behavior of Ni-base superalloy with different content of Cr, Ti and Ta was studied. The results show that the oxidation resistance of Cr, Ti, Ta alloy has different effects in different stages of oxidation. In the initial stage of oxidation, No.3 alloy with high Ti content has obvious weight gain on the oxidation curve due to the strong affinity between Ti element and O, while the No.1 alloy with high Cr content has a greater weight gain as the oxidation progresses This is due to the selective oxidation of Cr. In 1223 K, the low content of Ti and Ta in No.1 alloy can not form effective diffusion distribution in Cr2O3, and it is difficult to form continuous protective oxide film, which can not effectively hinder the continuous diffusion of Cr3 + into the alloy. The No.2 and No.3 alloy Ti and Ta moderate content, the formation of a continuous film can delay the continuous outward diffusion of Cr3 +, to improve the antioxidant capacity of the alloy has a positive effect.