高温抗氧化性能的影响
( 1. 大连理工大学 材料工程系， 大连 116024;
2. 沈阳材料国家（联合）实验室， 沈阳 110016；
3. Department of Materials Science and Engineering, University of California,
Los Angeles, CA 90095-1595, USA)
摘 要: 通过热处理获得了合金Ti-42.85Al-12.3Nb-2Cr铸态(As-cast)、 炉冷(FC)和水淬(WQ)3种含不同组成相和微观组织的合金， 研究了这3种合金在1000℃静止空气中的断续氧化行为， 采用XRD、 SEM和EPMA分析了氧化膜的结构和组成。 研究表明， Nb的加入能够显著提高合金的抗氧化性， 但是高含量Nb的加入导致高温亚稳β相在室温组织中残留， β相使外层氧化膜的粘附性变差， 促使氧化膜整体剥落。 通过热处理消除β相后， 获得的以γ+α2为主相的炉冷合金中形成了有效的保护性氧化膜。
关键字: Ti-Al-Nb合金；金属间化合物； 断续氧化； 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
