Effect of Cr on high temperature oxidation of TiAl
(1.北京市北京航空航天大学材料科学与工程学院
2.School of Materials Science and Engineering,Beijing University of Aeronautics and Astronautics, Beijing 100083, China)
2.School of Materials Science and Engineering,Beijing University of Aeronautics and Astronautics, Beijing 100083, China)
Abstract: The oxidation behavior of TiAl-Cr(mole fraction of Cr？0-20%) was investigated at 1 173 K in air. The microstructure and composition of the oxide scale were studied by X-ray diffractometry(XRD), scanning electron microscopy(SEM) and electro-probe micro-analyses(EPMA). The results show that with the addition of Cr content from 0 to 8%, the oxidation resistance decreases, especially at 3%, which is mainly attributed to the doping effect of Cr3+. TiAl-Cr(mole fraction of Cr？15%？20%) has good oxidation resistance, and the protective alumina layer is preferentially formed on the surface of TiAl alloy, which is due to an increase of mole ratio of Al to Ti in TiAl-Cr alloys.
Key words: TiAl; chromium; oxidation