(北京航空航天大学 材料科学与工程学院, 北京 100083)
摘 要: 利用Pt丝标记法和定量成分分析等研究方法， 研究Ti-Al(2%～75%Al, 摩尔分数)合金在1 173 K的大气中经24 h氧化形成的氧化膜的组织形态和生长过程。 结果表明: 在氧化膜中观察到Al2O3存在3种不同分布形式， 即当2%＜x(Al)＜25%时， Al2O3集中地分布在外层氧化膜中； 当30%＜x(Al)＜55%时， Al2O3同时分布在内层和外层氧化膜中； 而当x(Al)＞65%时， 氧化膜由单一的Al2O3构成。 Ti-Al合金高温氧化膜中Al2O3和TiO2的分布可分为4种组织形态。 采用Pt标记可清晰观察到氧化膜内、 外层， 外层氧化膜的形成与Al离子向外扩散有关， 内层氧化膜的形态受MO/M界面热力学平衡控制。
关键字: Ti-Al合金; 高温氧化; 氧化膜； 界面热力学
high-temperature oxide films of Ti-Al alloys
（School of Materials Science and Engineering,
Beijing University of Aeronautics and Astronautics, Beijing 100083, China）
Abstract: The structure morphology and growth procedure of oxidation films that form in atmosphere at 1 173 K for 24 h oxidation on Ti-Al(2%-75%Al, mole fraction) alloys were investigated by Pt filament labelling method. The results show that the three different types of Al2O3 distribute in the oxidation films. When 2%＜x(Al)＜25%, Al2O3 concentrates in the outer layer; when 30%＜x(Al)＜55%, Al2O3 distributes both in the inner and outer layers; while x(Al)＞65%, the oxidation film is composed of single Al2O3. It is found that four morphologies of Al2O3 and TiO2 can be observed in high-temperature oxidation films of Ti-Al alloys. The interface between inner and outer oxidation films can be clearly determined by Pt labelling method. The formation of the outer film is related to the outward diffusion of Al ion in the oxidation film, and the morphology of inner oxidation films is controlled by the MO/M interface thermodynamics.
Key words: Ti-Al alloy; high-temperature oxidation; oxide films; interface thermodynamics
