Microstructure and mechanical properties of B6O-B4C sintered composites prepared under high pressure

Sintered composites in the B6O-xB(4)C (x = 0-40 vol%) system were prepared under high pressure and high temperature conditions (3-5 GPa, 1500-1800 deg rees C) from the mixture of in-laboratory synthesized B6O powder and commer cially available B4C powder. Relationship among the formed phases, microstr uctures and mechanical properties of the sintered composites was investigat ed as a function of sintering conditions and added B4C content. Microhardne ss of the sintered composite was found to increase with treatment temperatu re up to 1800 degrees C, while fracture toughness decreased slightly. Maxim um microhardness of Hv similar to 46 GPa was obtained from B6O-30vol%B4C si ntered composite under the sintering conditions of 4 GPa, 1700 degrees C an d 20 min. (C) 2000 Kluwer Academic Publishers.