Enhanced fracture properties of ZrB2-based composites by in-situ grown SiC nanowires

ABSTRACTTo improve the fracture properties of ZrB2-based composites, SiC nanowires (SiCnw) were introduced into the powder mixtures via an in-situ growth method and the composites were fabricated by hot pressing. Microstructure observations found that the SiCnw with a diameter of less than 100 nm presented twisted morphology and homogeneously distributed among ceramic particles. It was also found that the SiCnw could inhibit the grain growth of ZrB2-based composites. Compared to that of composites without SiCnw, the fracture toughness and the work of fracture for the composites with SiCnw were 7.17 MPa m1/2 and 205 J m−2, which increased by 61.1% and 91.6%, respectively. The main enhancing mechanisms could be associated with the obvious crack deflection, crack branching and pull out of SiCnw. The SiCnw could refrain the crack opening and reduce the stress intensity in front of crack tips, which absorbed more energy and improved the fracture properties.