Development of Y-modified Gamma TiAl through EPM

초록

Gamma TiAl alloys have a high potential for aerospace component applications because of their excellent specific strength up to 800℃. The oxidation resistance of the gamma alloys, however, is relatively weak compared to the Ni-base superalloys. In the present work, Y-modification of the chemical composition of the gamma alloy is shown to promote the oxidation resistance of the alloy in a hot air environment. In the alloys made through the elemental powder method, the role of Y was found to be twofold, scavenging of internal oxygen and blocking of the ingress of external oxygen. The former originated from the strong interaction between Y and O during powder consolidation while the latter was caused by the formation of thin multilayered oxide scale. As a result, not only the oxidation resistance but only also the high temperature strength of the alloy was substantially enhanced, making the gamma alloy a step closer to commercial application.