Effect of Al and TiO2 on sinterability and mechanical properties of boron carbide

B4C matrix ceramics with different content of Al and TiO2 were fabricated by hot-press sintering, and sinterability of B4C matrix ceramics was investigated by addition of TiO2 and Al. X-ray diffraction analysis showed that in situ reaction between B4C and TiO2 happened, and TiB2 was formed during sintering. Vickers hardness, fracture toughness and flexural strength of the fabricated composites were measured. Results showed that the densification rate and mechanical properties of B4C matrix ceramics were significantly improved due to the introduction of TiO2 and Al. The eliminating of B2O3 (impurity in B4C) and the interface reaction contributed to the densification rate. The enhanced flexural strength was obtained owing to change of fracture mode and the improvement in fracture toughness was due to the formation of microcracks and deflection of propagating cracks caused by the thermal expansion mismatch between TiB2 and B4C matrix.