In-situ HIP synthesis of TiB2/SiC ceramic composites

Abstract

Dense TiB 2 /SiC ceramic composites were fabricated by means of in-situ HIP synthesis processing from TiH 2 , Si, C and B 4 C powder blends. The microstructure and mechanical properties of the ceramic matrix composites were investigated using X-ray diffraction, optical microscopy, scanning electron microscopy, transmission electron microscopy and microhardness. The grains of TiB 2 and SiC in the ceramic matrix composites are fine, the TiB 2 grains being regular-platelet, and the SiC grains being are irregular polygon. The mechanical properties of the composite are mainly affected by their densities. As the density increases, the properties of the composites improve. The microhardness, fracture toughness K IC and flexural strength are, respectively, 14.80 GPa, 4.75 MPa m 1/2 and 408.62 MPa in the 96% density TiB 2 /SiC composites. The crack propagation path is deflected in these composites. TiB 2 /SiC composites also have an excellent oxidation resistance. The average oxidation rate of TiB 2 /SiC is about 10 −10 m s −1 from 1073 to 1473 K.