High strength B4C–TiB2 composites fabricated by reaction hot-pressing

Abstract B 4 C based composites with 20 mol% TiB 2 were fabricated by reaction hot-pressing of four different submicron size B 4 C powders with the addition of nanometer size TiO 2 and C powders at 2000 °C, and their mechanical properties were examined. A B 4 C–TiB 2 composite with both high strength of 866 MPa and modest fracture toughness of 3.2 MPa m 1/2 could be obtained using B 4 C powder with a mean particle size of 0.50 μm and total metal impurity 0.3–0.5 wt.% (Al + Fe). It seems that this extremely high strength is attributed to the fine-grained B 4 C microstructure, uniform dispersion of TiB 2 particles and improvement of fracture toughness.