( 1. 北京科技大学 材料科学与工程学院， 北京 100083;
2. Notional Institute for Materials Science, Tsukuba 305-0047, Japan;
3. Japan Society for Promotion of Science, Tokyo 102-8471, Japan)
摘 要: 研究了均匀化和铸态TiAl合金在(Na, K)2SO4混合熔盐中的热腐蚀行为，讨论了α2相在均匀化和铸态TiAl合金热腐蚀中的作用机理。 结果表明： 含少量α2相的均匀化TiAl合金呈现良好的抗热腐蚀行为， 腐蚀产物中的富Al2O3相成层状分布，在腐蚀产物/基体界面形成连续的富Ti硫化物； 而含有大量层状组织的铸态TiAl合金则遭受严重的热腐蚀， 在腐蚀初期， α2+γ构成的层状组织优先腐蚀， 铸态TiAl合金的腐蚀层主要由富Ti的氧化物和硫化物组成， 形成的混合膜黏附性差，较易剥落。
关键字: TiAl金属间化合物；高温热腐蚀； 熔融硫酸盐
hot corrosion behavior of TiAl intermetallics
（ 1. School of Materials Science and Engineering,
University of Science and Technology Beijing,
Beijing 100083, China;
2. National Institute for Materials Science,
Tsukuba 305-0047, Japan;
3. Japan Society for the Promotion of Science,
Tokyo 102-8471, Japan）
Abstract: The hot corrosion behavior of as-cast and homogenized TiAl intermetallics was studied in (Na, K)SO4 mixed melts at 900℃, and the mechanism of the hot corrosion was discussed. The results show that microstructure of the homogenized TiAl is composed of uniform γ phase and some α particles. For the as-cast TiAl, however, its microstructure consists of 30% γ phase and 70% (γ+α2 ) lamellar structures. Hot corrosion resistance is high in the homogenized TiAl. The corrosion products are Al2O3. There is a layer of Ti sulfide on the interface between TiAl substrate and the corrosion products. The as-cast TiAl intermetallics is poor in hot corrosion property. α2 phase in the lamellar structure is corroded preferentially because of higher Ti element content in α2 phase. Corrosion product for the as-cast TiAl consists of Ti oxide and sulfide that can be easily peeled off from the substrate.
Key words: TiAl intermetallics； hot corrosion； molten sulfate
