Oxidation behavior of Ti2AlC/TiAl composites
(School of Materials Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China)
Harbin Institute of Technology, Harbin 150001, China)
Abstract: The oxidation behavior of Ti-34Al alloy and Ti2AlC/TiAl composites was studied at temperatures ranging from 800 to 1000℃. Results show that the oxidation resistance of Ti2AlC/TiAl composites is lower than that of TiAl alloy, and the growth rate of the oxidation scale increases with increasing addition of Ti2AlC. The oxidation resistance of Ti2AlC/TiAl composites significantly decreases at 900℃ and the mass gain is above ten times that at 800℃. However, the mass gain is lowered when exposed at 1000℃. The oxidation kinetics of the Ti2AlC/TiAl composites is very complicated, including linear laws and parabolic laws under different conditions. The oxidation scale of the composites is composed of R-TiO2 and α-Al2O3 at 800℃, and R-TiO2 at 900℃ and 1000℃. The R-TiO2 is columnar and grows with increasing oxidation temperature and volume fraction of Ti2AlC.
Key words: TiAl-matrix composites; oxidation; Ti2AlC