Nb、Mo对TiAl基合金高温氧化行为的协同效应研究

Synergistic Effect of Nb and Mo on the Oxidation Behavior of TiAl-based Alloys

摘要:

本文采用冷坩埚悬浮熔炼技术制备Nb、Mo合金化的TiAl基合金，研究合金在大气环境中的高温长时氧化行为。采用X射线衍射、扫描电镜及能谱分析研究氧化层的相结构、显微组织及与基体合金的界面特征，结合氧化动力学测试研究Nb、Mo对TiAl基合金高温抗氧化行为的协同效应。结果发现，Nb、Mo协同作用较单一元素合金化的TiAl合金具有更为优良的高温抗氧化性，连续致密且与基体良好结合的氧化膜可明显降低合金的氧化速率、减小氧化增重。Nb、Mo掺杂的TiAl基合金氧化层可阻止氧原子向内扩散，Nb、Mo的协同效应有助于改善TiAl基合金的高温抗氧化性。

Abstract:

TiAl-based alloys with Nb/Mo were obtained by the cold crucible induction levitation melting method. The oxidation behavior in air at 900℃ for various time were investigated. The phase composition, microstructure and the interface of oxidation film and matrix were investigated with the help of XRD, SEM equipped with EDS. Combined with the oxidation kinetic analysis, it is expected to explore the synergistic effect of Nb and Mo on the oxidation behavior of TiAl-based alloys. With the addition of Nb and Mo, the continuous compact oxidation film decreases the oxidating rate and the mass gain which makes alloy preserve better oxidation properties comparing with that of Ti-46Al-6Nb. Due to the synergistic effect of Nb and Mo, the indiffusion of oxygen atoms could be prevented and the oxidation properties of TiAl-based alloys could be improved significantly.