Oxidation of Ni-rich Ni-Al intermetallics
The oxidation of Ni-Al intermetallic alloys in the beta-NiAl phase field and in the two phase beta-NiAl/gamma'-Ni{sub 3}Al phase field has been studied between 1000 and 1400 C. The stoichiometric beta-NiAl alloy doped with Zr was superior to other alloy compositions under cyclic and isothermal oxidation. The isothermal growth rates did not increase monotonically as the alloy Al content was decreased. The characteristically ridged alpha-Al{sub 2}O{sub 3} scale morphology, consisting of cells of thin, textured oxide with thick growth ridges at cell boundaries, forms on oxidized beta-NiAl alloys. The correlation of scale features with isothermal growth rates indicates a predominant grain boundary diffusion growth mechanism. The 1200 C cyclic oxidation resistance decreases near the lower end of the beta-NiAl phase field.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
- OSTI ID:
- 5566269
- Report Number(s):
- N-89-15233; NASA-TM-101455; E-4438; NAS-1.15:101455; CONF-8809190-
- Resource Relation:
- Conference: Workshop on the oxidation of high-temperature intermetallics, Cleveland, OH (United States), 22-23 Sep 1988
- Country of Publication:
- United States
- Language:
- English
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