Densification and Mechanical Properties of B₄C Based Composites Sintered by Reaction Hot-Pressing

Boron carbide (B4C) possesses unique physical and thermal properties. In this paper, B4C based composites toughened by TiB2 were fabricated by in-situ reaction sintering with the original microcrystalline powders B4C, TiO2 and glucose. The influences of sintering temperature and content of TiO2 on the sintering behavior and mechanical properties were investigated. (TiB2, Al2O3)/B4C and (TiB2,SiC)/B4C composites with almost fully dense were fabricated by using additives　of Al2O3 and Si powders and sintering at 1950C and 1900C, the fracture toughness of composites reach to 7.09 and 6.35 MPa•m1/2 respectively. The analysis of microstructure shows that the main toughen mechanism is the crack deflection due to the existence of residual stress.