SHI Ruixia, YIN Yansheng, LI Aiju, ZHEN Yuhua

(Shandong University, 250061)

Abstract: The fracture toughness of B₄C multiphase ceramics prepared by hot -pressed methods at 1800 ℃ reached 12.88 MPa·m^{1/ 2} . The thermal expansion coefficients of SiC and TiC do not match with B₄C matrix' .The improvement of the    composite toughness resulted from the multitoughening of both the crack deflection associated with the incorporation of SiC and TiC particulates and rodlike β -Si₃N₄ produced by α-Si₃N₄.

Keywords: composite ceramics,multitoughening, B₄C