Pressureless sintering of internally synthesized SiC-TiB2 composites with improved fracture strength

Abstract SiC-TiB 2 particulate composites were fabricated by converting TiO 2 to TiB 2 through the reaction between TiO 2 , B 4 C and C. The presence of initially very fine, in-situ created, TiB 2 particles increased driving force for sintering and enabled fabrication of a dense composite utilizing pressureless sintering and the liquid phase created between Al 2 O 3 and Y 2 O 3 additives. The effect of volume fraction of the in-situ formed TiB 2 on density, microstructure and flexural strength was discussed. It was found that the presence of TiB 2 particles suppressed the growth of SiC grains and enhanced fracture strength. The fracture strength of samples containing 12 vol% TiB 2 was more than 30% higher than that of the monolithic SiC. The effect of SiC grain size on fracture strength was also analyzed.