Mechanical properties of boron carbide ceramics

Mechanical properties of BC ceramics hot-pressed with no additive and CrB, particles distributed in the B4C matrix were measured. The flexural strength of 675 MPa and the fracture toughness of 2.5 MPa (.) m(1/2) for the B4C ceramics sintered at 1900degreesC with no additive were obtained. This high strength is attributed to the fine grained microstructure, which could be produced by hot-pressing at low temperature without significant grain growth using the fine B4C powder. No profound influence on fracture toughness was shown with increasing CrB, content from 5 to 15 mol%. At 20 mol% CrB, the fracture toughness was improved to 3.5 MPa . m(1/2) due to some deflection of propagating cracks, and the flexural strength of 630 MPa was obtained.