High-temperature oxidation of Ti-48Al-2Nb-2Cr and Ti-25Al-10Nb-3V-1Mo
- Los Alamos National Lab., NM (United States). Materials Science and Technology Div.
The short-term oxidation behavior of a {gamma}-TiAl alloy (Ti-48Al-2Nb-2Cr) was compared and contrasted to that of an {alpha}{sub 2}-Ti{sub 3}Al base (Ri-25Al-19Nb-3V-1Mo) alloy. Oxidation of Ti-25Al-10Nb-3V-1Mo was found to occur at a moderate rate at 800 C, in a N{sub 2} + 20% O{sub 2} environment. A large increase in the oxidation rate occurred above this temperature. This large weight increase was attributed to a breakdown in the protective oxide scale on the surface of the {alpha}{sub 2} intermetallic alloy, thereby permitting rapid diffusion of oxygen and nitrogen to the surface of the intermetallic. The oxidation rate of this alloy at 1,200 C was not significantly higher than the oxidation rate at 1,000 C. In contrast, the oxidation rate of Ti-48Al-2Nb-2Cr remained low up to 1,200 C. At this temperature, a significant increase in oxidation was observed and was attributed to accelerated oxygen diffusion through the {alpha}{sub 2} phase and increased solubility of oxygen in the {gamma} phase of the intermetallic microstructure. This weight increase occurred despite the fact that at 1,200 C, the integrity of the oxide layer formed on the surface of this alloy was maintained. The results of this study illustrate the need for developing protective environmental coatings tailored to the individual intermetallic alloy.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 651052
- Journal Information:
- Oxidation of Metals, Vol. 50, Issue 3-4; Other Information: PBD: Oct 1998
- Country of Publication:
- United States
- Language:
- English
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