Y，La改性Ni-10Cr-5Al合金的循环氧化行为研究

通过添加0.1%(质量分数)的单一稀土La和复合稀土Y-La,研究了两种含稀土的Ni-10Cr-5Al(质量分数,%)合金在1 100℃和1 200℃下的高温循环氧化行为。采用热重法并结合X射线衍射、扫描电子显微镜、能谱仪等,研究了合金的循环氧化动力学、氧化物的物相和组织成分等演变规律,分析了含稀土Ni-10Cr-5Al合金的氧化膜粘附性能在不同氧化温度下的差异及机制。结果表明,在1 100℃时,Ni-10Cr-5Al合金中添加0.1%(质量分数)的La或Y-La,不仅减少了氧化膜的厚度,而且因形成"钉扎"作用提高了氧化膜的粘附性,从而改善了合金的抗循环氧化性能。且复合添加Y-La的效果优于单一添加La的效果。但在1 200℃时,合金沿晶界的内氧化加快,反而恶化了合金的抗循环氧化性能。

Study on Cyclic Oxidation Behavior of Y and La Modified Ni-10Cr-5Al Alloys

The cyclic oxidation behavior of Ni-10Cr-SAl (mass fraction,％) alloys containing 0.1 ％ (mass fraction) La or Y-La at 1 100 ℃ and 1 200 ℃ was studied.The kinetics of cyclic oxidation of the alloys were studied by means of thermogravimetric analysis,and the evolution rules of phase,microstructure and composition of the oxides were studied by X-ray diffraction and scanning electron microscopy with energy-dispersive X-ray spectroscopy.The difference of the adhesion of the surface scale of Ni-10Cr-5Al alloys containing La or Y-La at different oxidation temperature was analyzed.The results indicated that the addition of 0.1％ (mass fraction) La or Y-La in Ni-10Cr-5Al alloy could not only reduce the thickness of the oxide film,but also improve the adhesion of the oxide film due to the formation of "pinning",thus the anti-oxidation performance at 1 100 ℃ of the alloys were improved.While the effect of co-doping Y-La was better than that of single adding of La.However,the anti-oxidation performance at 1 200 ℃ of the alloys was deteriorate owing to the severe internal oxidation along the grain boundary.