( 1. 北京科技大學 材料科學與工程學院， 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: 研究了均勻化和鑄態(tài)TiAl合金在(Na, K)2SO4混合熔鹽中的熱腐蝕行為，討論了α2相在均勻化和鑄態(tài)TiAl合金熱腐蝕中的作用機理。 結(jié)果表明： 含少量α2相的均勻化TiAl合金呈現(xiàn)良好的抗熱腐蝕行為， 腐蝕產(chǎn)物中的富Al2O3相成層狀分布，在腐蝕產(chǎn)物/基體界面形成連續(xù)的富Ti硫化物； 而含有大量層狀組織的鑄態(tài)TiAl合金則遭受嚴重的熱腐蝕， 在腐蝕初期， α2+γ構(gòu)成的層狀組織優(yōu)先腐蝕， 鑄態(tài)TiAl合金的腐蝕層主要由富Ti的氧化物和硫化物組成， 形成的混合膜黏附性差，較易剝落。
關鍵字: TiAl金屬間化合物；高溫熱腐蝕； 熔融硫酸鹽
hot corrosion behavior of TiAl intermetallics
K. Hashimoto3, CHU Wu-yang1
（ 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
