Experimental investigation of the dynamic elastic modulus and vibration damping in molybdenum and alumina-coated Ti-25Al-10Nb-3V-1Mo aluminides cycled at elevated temperatures
- Texas A&M Univ., College Station, TX (United States)
- Los Alamos National Lab., NM (United States)
Titanium aluminides such as Ti-25Al-10Nb-3V-1Mo have became the focus of high temperature materials research due to their ability to maintain their strength up to 1,000{degree}C. However, at temperatures in excess of 650{degree}C, Ti-25Al-10Nb-3V-1Mo undergoes severe oxidation which, in turn, can degrade its mechanical properties. To address this problem, plasma sprayed coatings were applied to the substrate to provide protection in the high temperature environment. In this study, 0.1-0.125 mm thick alumina and molybdenum coatings were plasma sprayed onto a Ti-25Al-10Nb-3V-1Mo substrate. Changes in dynamic elastic modulus and vibration damping due to thermal cycling at elevated temperatures were measured. The modulus and damping were measured using the piezoelectric ultrasonic composite oscillator technique (PUCOT). The behavior of the Al{sub 2}O{sub 3} and Mo coated specimens was compared to that of the uncoated samples. Thermal cycling of the coated samples at 600{degree}C led to an increase in the modulus and decrease in the damping. Most of the changes in properties occurred after the first thermal cycle. Thermal cycling of the samples at 750{degree}C and 850{degree}C led to complete failure of the coatings. A specimen with a 1.0 mm alumina coating exhibited cracks even when cycled at 600{degree}C. 7 refs., 12 figs., 3 tabs.
- OSTI ID:
- 263168
- Journal Information:
- Journal of Advanced Materials, Vol. 27, Issue 3; Other Information: PBD: Apr 1996
- Country of Publication:
- United States
- Language:
- English
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