(1. 北京航空航天大学 材料科学与工程学院，北京 100191；
2. 中国商用飞机有限责任公司，上海 200232；
3. 中国人民公安大学 继续教育学院，北京 100076)
摘 要: 采用热重分析(TG)、X射线衍射(XRD)、透射电镜(TEM)及能谱分析(EDS)等方法，研究Nb-Si-Ti(15%~ 26%，摩尔分数)-Hf-Al-Cr多元合金、Nb-Ti(0~50%)二元合金在1250 ℃大气中的高温氧化行为。通过Ti含量变化对合金氧化产物种类及氧化物PBR值的影响，探讨Ti含量对Nb基合金高温抗氧化性能的作用。结果表明：随着Ti含量的增加，合金的高温氧化产物从Nb2O5、Ti2Nb10O29、TiNb2O7和TiO2依次过渡。通过计算发现：Nb基合金的氧化产物Nb2O5、Ti2Nb10O29、TiNb2O7及TiO2的PBR值随着Ti含量的升高依次减小。氧化产物PBR值的下降，可以有效地降低Nb基合金氧化膜的生长应力、提高氧化膜的完整性、增大氧化膜的失效周期，提高Nb基合金的高温抗氧化性能。
关键字: 高温合金；Nb基合金；高温抗氧化性能；氧化产物
（1. School of Materials Science and Engineering, Beihang University, Beijing 100191, China;
2. Commercial Aircraft Corporation Ltd. of China, Shanghai 200232, China;
3. College of Extended Education, People’s Public Security University of China, Beijing 100076, China）
Abstract:The high temperature oxidation behaviors of Nb-Si-Ti(15%-26%, mole fraction)-Hf-Al-Cr and Nb-Ti (0-50%) alloys at 1250 ℃ were analyzed utilizing oxidation weight gain method. The scale morphology and composition were studied by X-ray diffractometry (XRD), transmission electron microscopy (TEM) and EDS analysis. The relationships among the Ti content and the oxidization products and their Pilling-Bed-Worth ratio (PBR, φ) values were further studied. The results show that as the Ti content in the Nb-based alloys increases, the oxidization products transform from Nb2O5 to Ti2Nb10O29 first, then to TiNb2O7 and finally to TiO2. Their corresponding PBR values decrease in sequence. With the decrease of PRB values, the growth stress decreases, the integrity improves and failure cycle lengthens in the oxide film. Therefore, the high temperature oxidation resistance of the Nb-based alloys is significantly improved.
Key words: superalloy; Nb-based alloy; high temperature oxidation resistance; oxidization product
