Fiber Reinforced Ceramic Matrix Composites.
Final rept. 15 Jan 72-15 Jan 73,
UNITED AIRCRAFT RESEARCH LABS EAST HARTFORD CONN
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Tungsten reinforced silicon nitride was found to increase the elevated temperature 1300C Charpy impact strength by a factor of nine over monolithic Si3N4, primarily due to the energy absorbing mechanism of fiber pullout. However, the room temperature Charpy impact strength of tungsten reinforced Si3N4 is not increased over that of monolithic Si3N4 due to the brittle nature of the silicide reaction product at the Si3N4-W interface and the notch sensitivity of tungsten. Tantalum wire reinforced Si3N4 was found to increase the room temperature Charpy impact strength of Si3N4 by a factor of 30 0.5 ft-lbs to 14.8 ft-lbs and also to affect the mode of failure such that interfacial splitting along with ductile fiber elongation occurs, resulting in very small fragments of matrix breaking off upon impact. This mode of fracture is desirable for use in gas turbine engines. Author Modified Abstract
- Laminates and Composite Materials
- Jet and Gas Turbine Engines