OXIDATION BEHAVIOR OF BINARY TI-AL ALLOYS IN HIGH-TEMPERATURE AIR ENVIRONMENT

The oxidation behavior of binary Ti-Al alloys containing 20 to 63 mass%Al was studied in air at 1073 to 1173 K. For alloys containing less than 51%Al multi-layered scale was formed accompanying internal oxidation zone in the base metal giving smaller oxidation resistance, while for 63%Al alloy protective scale was formed. The relationship between the scale morphology and the oxidation behavior was examined and the breakaway oxidation behavior observed in the alloys was interpreted by the stability in the continuity of the second from outer Al2O3 scale layer. The internal oxidation behavior was examined and discussed in terms of various influences on the overall oxidation behavior.