合金元素对一种镍基高温合金850℃氧化行为的影响

Effects of Alloying Elements on Oxidation Behavior of a Superalloy at 850℃

研究了不同Ti、Cr、Ta含量定向凝固高温合金的850℃恒温氧化行为。结果表明:Ti、Cr、Ta对合金的抗氧化性能作用各异。在氧化初期,Ti元素与O的亲和力很强,含Ti含量高的3#合金在氧化曲线上增重较为明显,而随着氧化的推进,氧化过程受到Cr的选择性氧化控制,由于三种合金中都有足够含量的Cr元素可以形成稳定的具有保护性的Cr2O3氧化膜,可有效地阻碍氧化向基体的进一步扩散。在整个氧化过程中,Ta的添加可增强氧化膜粘附性,提高合金抗氧化性能,但由于三种合金中Ta的添加量上的差异,在氧化过程中体现的不明显。

The isothermal oxidation behavior of superalloys with different Cr, Ti and Ta content were investigated. The results showed that the different compositions play a different role. In prime oxidation, the oxidation mass gain of 3# alloy with high Ti content increased obviously duo to the strong appetency between Ti and O. Following with the continuous oxidation, the oxidation process was controlled by the selective oxidation of Cr. The steady protective Cr2O3 oxidation scale could be formed due to the suffice Cr content in the alloys, which could postpone the further diffusion of oxidation to the matrix. During the oxidation process, Ta enhanced the adhesivity of oxidation scale and improved the anti-oxidation performance of the alloy. Because the oxidation scale did not lose, the role of the different Ta addition on oxidation behavior was unconspicuous.