Dy对NiAl-31Cr-3Mo合金循环氧化性能的影响

Effect of Dysprosium on Cyclic oxidation of NiAl-31Cr-3Mo Alloy

研究了稀土元素Dy对NiAl-31Cr-3Mo合金在1300和1400 K空气中的循环氧化行为的影响。结果表明:稀土元素Dy的添加显著提高了基体合金的抗循环氧化性能。X射线衍射与SEM分析表明:基体合金表面氧化膜主要由-αAl2O3构成,并含有少量的Cr2O3,而添加稀土元素Dy后,合金表面形成了单一的-αAl2O3氧化膜,在氧化膜与基体合金之间形成一层富Cr相,大大提高了氧化膜的粘附性,从而提高了合金的抗循环氧化性。采用EDAX分析研究了合金表面氧化产物的微观组织及成分,并从合金相组成探讨了稀土元素Dy提高基体NiAl-31Cr-3Mo合金的抗循环氧化性能的机制。

The effect of dysprosium on the cyclic oxidation behavior of NiAl-31Cr-3Mo alloy at 1300 and 1400 K at static air atmosphere was investigated. The results reveal that doping 0. 1% Dy （atom fraction ） greatly improves cyclic oxidation resistance of the alloy. The microstructure and composition of the oxide layer were studied by means of X-ray diffraction （XRD） and scanning electron microscopy （SEM） with EDAX unit. The oxidation scale which was located on the surface of NiAl-31Cr-3Mo alloy mainly consists of α- Al2O3 and a little Cr2O3 without Dy. While the continuous and sole α- Al2O3 scale formed on the surface of the alloys doped with dysprosium. The adhereney of scale improves due to Cr-rieh phase decreases the internal stress by thermal cycling and transformation of Al2O3 or transverse growing induced. The oxidation mechanism is discussed from phase constitution.