Microstructure and mechanical properties of silicon carbide monofilament reinforced zirconium diboride matrix composites

Unidirectional SiC monofilament-reinforced ZrB2 matrix composites were fabricated by hot pressing at 2173 K for 1 h under a uniaxial load of 30 MPa. The fracture toughness of SiC monofilament-reinforced ZrB2 matrix composites was 6.1 MPa m1/2, which was much higher than that of monolithic ZrB2 and SiC particles reinforced ZrB2 matrix composites. The improvement of toughness for SiC monofilament-reinforced ZrB2 matrix composites was mostly attributed to the addition of the SiC monofilament, which could activate fiber pull-out and crack deflection. In addition, the high strength of SiC monofilament itself was also a major reason for the improvement of toughness of SiC monofilament-reinforced ZrB2 matrix composites.