B4C−CrB2 composites with improved mechanical properties

B4C based ceramic composites with 0−25 mol% CrB2 were fabricated by hot-pressing at 1900 °C, and their mechanical properties were examined. The B4C−CrB2 composites with both high strength of 630 MPa and modest fracture toughness of 3.5 MPa m1/2 could be obtained by the addition of 20 mol% CrB2. It seems that improvement in fracture toughness is due to the formation of microcracks and deflection of propagating cracks caused by the thermal expansion mismatch between CrB2 and B4C.