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The mechanical behavior of continuous fiber-reinforced SiC/RBSN composites with various fiber contents is evaluated. Both catastrophic and noncatastrophic failures are observed in tensile specimens. Damage and failure mechanisms are identified via in-situ monitoring using NDE techniques throughout the loading history. Effects of fiber/matrix interface debonding (splitting) parallel to the fibers are discussed. Statistical failure behavior of fibers is also observed, especially when the interface is weak. Micromechanical models incorporating residual stresses to calculate the critical matrix cracking strength, ultimate strength, and work of pull-out are reviewed and used to predict composite response. For selected test problems, experimental measurements are compared to analytic predictions.

A comprehensive process model for silicon carbide growth by modified Lely method is developed that accounts for irregular geometry, induction heating, radiative and conductive heat transfer, and growth kinetics. The growth kinetics is incorporated to predict the growth rate that is a strong function of temperature, temperature gradient and inert gas pressure.

This paper describes high-temperature reliability, particularly creep and creep rupture behavior of three engineering ceramics--silicon nitride, silicon carbide, and alumina-based silicon-carbide-particulate ceramics--which are considered the most potential candidates for the use of blades of high-efficiency ceramic gas turbine. The structural reliability of silicon nitride is very often limited due to the softening of glassy phases formed at grain boundaries. On the other hand, silicon carbide, which generally does not contain glassy phase at the grain boundaries, shows excellent creep resistance even at very high temperatures. Finally, it is shown that creep resistance of alumina can be markedly improved by dispersing nano-sized silicon carbide particles into the grain boundary. [DOI: 10.1115/1.1347990] Keywords: Ceramic Gas Turbine, Creep Resistance, High Temperature, Silicon Nitride, Silicon Carbide, Alumina