Mechanical behavior at 20 and 1200 C of Nicalon-silicon-carbide-fiber-reinforced alumina-matrix composites
- Polytechnic Univ. of Madrid (Spain). Dept. of Materials Science
Tensile and fracture tests were conducted at 20 and 1,200 C on a ceramic-matrix composite that was composed of an alumina (Al{sub 2}O{sub 3}) matrix that was bidirectionally reinforced with 37 vol% silicon carbide (SiC) Nicalon fibers. The composite presented nonlinear behavior at both temperatures; however, the strength and toughness were significantly reduced at 1,200 C. In accordance with this behavior, matrix cracks were usually stopped or deflected at the fiber/matrix interface, and fiber pullout was observed on the fracture surfaces at 20 and 1,200 C. The interfacial sliding resistance at ambient and elevated temperatures was estimated from quantitative microscopy analyses of the saturation crack spacing in the matrix. The in situ fiber strength was determined both from the defect morphology on the fibers and from the size of the mirror region on the fiber fracture surfaces. It was shown that composite degradation at elevated temperature was due to the growth of defects on the fiber surface during high-temperature exposure.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 549929
- Journal Information:
- Journal of the American Ceramic Society, Vol. 80, Issue 10; Other Information: PBD: Oct 1997
- Country of Publication:
- United States
- Language:
- English
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