Oxidation behavior of SiC/TiAl composite material

SiC fiber reinforced intermetallic is one of the promising candidate material for the next generation space plane, because of its excellent high temperature specific strength and elastic modulus. Oxidation behavior of the fiber-reinforced intermetallic (FRIM) is one of the most important properties for the practical use in the severe environment. Recently fabrication process of CVD-SiC fiber reinforced gamma-TiAl matrix composite has been developed. Oxidation behavior of SiC/gamma-TiAl and gamma-TiAl was studied. Cyclic oxidation experiments were executed at 900 degrees C under the dry airflow for 200 hours. Mass gains of the specimens were measured. The cross sections of specimen were observed by optical microscope. Mass gain of the SiC/gamma-TiAl composite material was two times larger than that of gamma-TiAl. Surface of the SiC/gamma-TiAl composite was covered with a comparatively thick oxide scale. Furthermore, formation of the oxide at the vicinity of interface between SiC fiber and gamma-TiAl matrix was observed. Oxidation mechanism of SiC/gamma-TiAl composite was discussed.