高溫抗氧化性能的影響
( 1. 大連理工大學(xué) 材料工程系， 大連 116024;
2. 沈陽材料國家（聯(lián)合）實(shí)驗室， 沈陽 110016；
3. Department of Materials Science and Engineering, University of California,
Los Angeles, CA 90095-1595, USA)
摘 要: 通過熱處理獲得了合金Ti-42.85Al-12.3Nb-2Cr鑄態(tài)(As-cast)、 爐冷(FC)和水淬(WQ)3種含不同組成相和微觀組織的合金， 研究了這3種合金在1000℃靜止空氣中的斷續(xù)氧化行為， 采用XRD、 SEM和EPMA分析了氧化膜的結(jié)構(gòu)和組成。 研究表明， Nb的加入能夠顯著提高合金的抗氧化性， 但是高含量Nb的加入導(dǎo)致高溫亞穩(wěn)β相在室溫組織中殘留， β相使外層氧化膜的粘附性變差， 促使氧化膜整體剝落。 通過熱處理消除β相后， 獲得的以γ+α2為主相的爐冷合金中形成了有效的保護(hù)性氧化膜。
關(guān)鍵字: Ti-Al-Nb合金；金屬間化合物； 斷續(xù)氧化； 抗氧化性
Ti-42.85Al-12.3Nb-2Cr alloy
（ 1. Department of Materials Engineering,
Dalian University of Technology, Dalian 116024, China;
2. Shenyang National Laboratory for Materials Science, Shenyang 110016, China;
3. Department of Materials Science and Engineering,
University of California,
Los Angeles, CA 90095-1595, USA）
Abstract: Three types of Ti-42.85Al-12.3Nb-2Cr alloys(as-cast, furnace cooled(FC) and water quenched(WQ)) with different phase compositions and microstructures were prepared. Interrupted oxidation behaviors of these alloys at 1000℃ in static air were studied using oxidation mass gain analysis. The structure and component of the oxide scales were analyzed by XRD, SEM and EPMA. Results indicate that Nb addition enhances oxidation resistance of the alloy, nevertheless high content of Nb results in the metastable β phase existing in the room-temperature structure. The existence of β phase makes the adhesion of the oxide become worse and accelerate the spalling of the oxide. In the FC alloy with main phase of γ+α2, a protective oxide scale forms after eliminating β phase in the alloy by heat treatment.
Key words: Ti-Al-Nb alloy; intermetallics; interrupted oxidation; oxidation resistance
