NiAl-28Cr-6Mo共晶合金的高温氧化行为

本文采用恒温氧化实验方法,在900~1150℃下测试了NiAl-28Cr-6Mo共晶合金的氧化性能,分析了合金的氧化动力学,SEM观测了合金表面以及横截面的形貌。研究表明,NiAl-28Cr-6Mo共晶合金在900~1100℃下合金表面生成了连续的Al_2O_3氧化膜,具有较好的抗氧化性能;900~1000℃氧化膜主要由θ-Al_2O_3和Cr_2O_3组成,随着恒温氧化温度的升高,θ-Al_2O_3和Cr_2O_3减少,α-Al_2O_3增多,1100℃下的氧化膜表面则主要由细小、致密的α-Al_2O_3组成;氧化过程中,表面氧化膜存在着θ-Al_2O_3→α-Al_2O_3的相变过程;θ-Al_2O_3较α-Al_2O_3的保护性差导致1000℃合金氧化增重大于1050℃和1100℃;1150℃下共晶合金氧化膜发生剥落,没有形成完整的Al_2O_3氧化膜导致合金的抗氧化性能恶化,氧化增重迅速增加。

High Temperature Oxidation Behavior of NiAl-28Cr-6Mo Eutectic Alloy

In this paper,using constant temperature oxidation test method,the oxidation performance of NiAl-28Cr-6Mo eutectic alloy was tested at 900~1150℃,the oxidation kinetics of the alloy was analyzed,and the morphology of the alloy surface and cross section was observed by SEM.Studies have shown that NiAl-28Cr-6Mo eutectic alloy forms a continuous Al2O3 oxide film on the alloy surface at 900~1100℃,with good oxidation resistance;900~1000℃oxide film is mainly composed ofθ-Al2O3 and Cr2O3 Composition,with the increase of constant temperature oxidation temperature,θ-Al2O3and Cr2O3 decrease,α-Al2O3increases,the surface of the oxide film at 1100℃is mainly composed of fine and denseα-Al2O3;during the oxidation process,the surface oxide film exists The phase transition process ofθ-Al2O3→α-Al2O3;the poor protection ofθ-Al2O3 compared toα-Al2O3 leads to the increase of the oxidation of the alloy at 1000℃over 1050℃and 1100℃;the oxide film of the eutectic alloy at 1150℃flakes and does not form The complete Al2O3 oxide film leads to the deterioration of the oxidation resistance of the alloy,and the weight gain of oxidation increases rapidly.