Matrix-grain-bridging contributions to the toughness of SiC composites with alumina-coated SiC platelets
- Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering
Silicon carbide composites were fabricated through the incorporation of alumina-coated SiC platelets into a SiC matrix. Mechanical properties were evaluated in direct comparison with a commercial Hexoloy SiC. The fracture toughness of the composite, with a fine grained {beta}-SiC matrix, was twice that of the commercial material. The alumina-coating on the platelets provided a weak interface to promote crack deflection and platelet bridging, as well as easing densification of the composites. On the other hand, a three-fold increase in fracture toughness (9.1 MPa {radical}m) of an in situ toughened monolithic SiC was achieved by processing at higher temperatures, promoting the {beta}-to-{alpha} phase transformation and forming a microstructure containing high-aspect-ration plate-shaped grains. Efforts were made to combine the effects of coated-platelets reinforcement and in situ toughening in the matrix. Moderate high toughness (8 MPa {radical}m) was achieved by coupled toughening. The contribution of matrix-grain-bridging, however, was limited by the processing temperature at which the oxide coating was stable.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 270809
- Report Number(s):
- LBNL-38880; CONF-9604124-12; ON: DE96013222; TRN: AHC29617%%141
- Resource Relation:
- Conference: 98. annual meeting of the American Ceramic Society, Indianapolis, IN (United States), 14-17 Apr 1996; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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