Silicon Carbide Platelet/Silicon Carbide Composites |
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Authors: | Tyrone Mitchell Jr † ‡ Lutgard C De Jonghe † ‡ Warren J MoberlyChan Robert O Ritchie† ‡ |
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Affiliation: | Center for Advanced Materials, Lawrence Berkeley Laboratory, Berkeley, California 94720 Department of Materials Science and Mineral Engineering, University of California at Berkeley, Berkeley, California 94720 |
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Abstract: | α-silicon carbide platelet/β-silicon carbide composites have been produced in which the individual platelets were coated with an aluminum oxide layer. Hot-pressed composites showed a fracture toughness as high as 7.2 MPa·m1/2. The experiments indicated that the significant increase in fracture toughness is mainly the result of crack deflection and accompanying platelet pullout. The coating on the platelets also served to prevent the platelets from acting as nucleation sites for the α- to β-phase transformation, so that the advantageous microstructure remains preserved during high-temperature processing. |
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