Characterization of Turbine Ceramics after Long-Term Environmental Exposure
Abstract
An experimental program was conducted to investigate the possible degradation in mechanical properties of silicon-based ceramics exposed to high temperature oxidizing environments. Thirteen materials were studied, all with potential for use in energy conversion devices such as the gas turbine. The materials ranged from some of the better known silicon nitrides and carbides to experimental grades. Testing included flexural stress rupture at 1200 C and stepped temperature stress rupture (STSR) experiments. The latter test was devised for this study and is a variation of the stress rupture test in which a range of temperatures is employed. The purpose of the STSR test is to explore the potential stress/temperature regimes of static fatigue failure. In addition, a combined cycle durability sequence was applied to selected materials. This procedure is a simple service simulation involving static heat soaks and rapid thermal cycling on bend bars. In nearly all cases, material degradation and/or time-dependent failure was observed. Extensive fractography was conducted to identify mechanisms of failure.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1980
- Accession Number
- ADA117463
Entities
People
- George D. Quinn
Organizations
- United States Army Research Laboratory