Microstructure of alumina-forming oxidation resistant Al-Ti-Cr alloys
- NASA Lewis Research Center, Cleveland, OH (United States)
Gamma-based titanium aluminides are currently being developed for intermediate temperature aircraft engine applications. This interest is due to their low density and to the identification of compositions and microstructures which possess both reasonable mechanical properties and some oxidation resistance. However, despite recent advances, oxidation resistant coatings for {gamma}-titanium aluminides are still needed. Therefore, as part of an overall effort to co-optimize the oxidation resistance and mechanical properties of Al-Ti-Cr alloys, an investigation of phase equilibria in the protective alumina-forming composition range at 1,073 K and 1,273 K was performed. Conclusions are as follows: (1) the protective alumina-forming Al-Ti-Cr alloys identified by Perkins et al. are based primarily on the {tau} (L1{sub 2}) and TiCrAl laves phases; (2) the {tau} phase in the multiphase protective alumina-forming Al-Ti-Cr alloys is not stable at 1,073 K and decomposes to r-Al{sub 2}Ti and Cr{sub 2}Al; (3) future coating alloy development in the Al-Ti-Cr system should focus on the {gamma}/TiCrAl laves two phase field.
- OSTI ID:
- 69660
- Journal Information:
- Scripta Metallurgica et Materialia, Journal Name: Scripta Metallurgica et Materialia Journal Issue: 10 Vol. 32; ISSN 0956-716X; ISSN SCRMEX
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM ALLOYS
CASTING
CHEMICAL COMPOSITION
CHROMIUM ALLOYS
CORROSION RESISTANT ALLOYS
ELECTRON MICROPROBE ANALYSIS
EXPERIMENTAL DATA
HEAT TREATMENTS
INTERMETALLIC COMPOUNDS
MICROHARDNESS
MICROSTRUCTURE
PHASE STUDIES
PRECIPITATION
SAMPLE PREPARATION
SCANNING ELECTRON MICROSCOPY
TITANIUM ALLOYS
X-RAY DIFFRACTION