(北京航空航天大學 材料科學與工程學院, 北京 100083)
摘 要: 利用Pt絲標記法和定量成分分析等研究方法， 研究Ti-Al(2%～75%Al, 摩爾分數(shù))合金在1 173 K的大氣中經(jīng)24 h氧化形成的氧化膜的組織形態(tài)和生長過程。 結(jié)果表明: 在氧化膜中觀察到Al2O3存在3種不同分布形式， 即當2%＜x(Al)＜25%時， Al2O3集中地分布在外層氧化膜中； 當30%＜x(Al)＜55%時， Al2O3同時分布在內(nèi)層和外層氧化膜中； 而當x(Al)＞65%時， 氧化膜由單一的Al2O3構(gòu)成。 Ti-Al合金高溫氧化膜中Al2O3和TiO2的分布可分為4種組織形態(tài)。 采用Pt標記可清晰觀察到氧化膜內(nèi)、 外層， 外層氧化膜的形成與Al離子向外擴散有關(guān)， 內(nèi)層氧化膜的形態(tài)受MO/M界面熱力學平衡控制。
關(guān)鍵字: Ti-Al合金; 高溫氧化; 氧化膜； 界面熱力學
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
