B_6.5C-TiB₂-SiC-BN composite ceramics were prepared by a novel solid-state reaction using TiCN, B, and Si as raw materials. The final products obtained by hot pressing at 1950 °C possessed a fine microstructure, homogeneous distribution, and excellent mechanical properties. The obtained bulk B_6.5C-TiB₂-SiC-BN composite ceramic shows a high relative density (98.8 %). The mechanical properties of the composites are anisotropic because of the orientation growth and structural characteristics of TiB₂ and h-BN grains. The values of hardness, bending strength, and fracture toughness measured along the hot-pressing direction were 19.6 GPa, 801 MPa, and 4.30 MPa m^1/2, respectively, which were higher than those measured perpendicular to the hot-pressing direction. The formation of twin structures in B_6.5C and SiC grains and the crack deflections induced by h-BN and TiB₂ grains are beneficial for improving the mechanical properties of these composites.

以TiCN，B和Si为原料，通过新型固相反应制备了B _6.5 C-TiB ₂ -SiC-BN复合陶瓷。通过在1950°C下热压获得的最终产品具有良好的微观结构，均匀的分布和出色的机械性能。所得的块状B _6.5 C-TiB ₂ -SiC-BN复合陶瓷显示出较高的相对密度（98.8％）。由于TiB ₂和h-BN晶粒的定向生长和结构特征，复合材料的机械性能是各向异性的。沿热压方向测得的硬度，弯曲强度和断裂韧性的值分别为19.6 GPa，801 MPa和4.30 MPa m ^1/2分别比垂直于热压方向测得的值高。B _6.5 C和SiC晶粒中双晶结构的形成以及h-BN和TiB ₂晶粒引起的裂纹变形有利于改善这些复合材料的机械性能。