Effects of Nb and Si on high temperature oxidation of TiAl

来源期刊：中国有色金属学报(英文版)2008年第3期

论文作者：姜惠仁 王中雷 马文帅 冯晓然 董自强 张亮 刘咏

文章页码：512 - 517

Key words：TiAl based alloy; niobium silicon alloying; isothermal oxidation behavior; oxidation resistance

Abstract: The isothermal oxidation behavior of TiAl based alloys at 900 ℃ in air with a combination of Nb (5%-10%, mole fraction) and Si (1%-5%, mole fraction) was investigated. The microstructure and the composition of the oxidation scale were studied by using XRD, TEM and EPMA. The results show that the combination of Nb and Si can improve the oxidation resistance of the alloys significantly. The element Si can change the typical microstructure of oxidation scale on TiAl based alloys. In alloys with Si addition, the compact Al₂O₃ forms in the interior side of oxidation scale. When x(Si)＞3%, the Ti₅Si₃ phase forms and the coarse crystal TiO₂ forms on Ti5Si3 phase after oxidation. The increase of Nb content in the TiAl based alloys impedes the growth of Ti₅Si₃ phase, and the formation of TiO₂ on surface and on Ti₅Si₃ phase is also impeded.