MECHANICAL PROPERTIES AND MICROSTRUCTURE OF Al₂O₃/TiB₂/SiC_w COMPOSITES

Al₂O₃/TiB₂/SiC_w composite was fabricated by hot pressing with SiC whiskers and TiB₂ as toughening phase. The mechanical properties and microstructure as well as toughening mechanisms were investigated. Results showed that the sintering temperature and the temperature holding time should be increased as the SiC_w content increased. Significant improvement in fracture toughness will be obtained for the Al₂O₃/TiB₂/SiC_w composite, in comparison with Al₂O₃/TiB₂ composite. Toughening mechanisms in the composite are mainly pullout of SiC whiskers crack deflection by TiB₂ grains and whiskers bridging.Considerable improvement in fracture toughness at high temperature was observed for the composite.