The effects of sintering temperature on the mechanical properties and toughening mechanisms of carbon fibre-reinforced HfB2-SiC composites

Abstract

HfB2-SiC composites were fabricated by the introduction of carbon fibres to meet the mechanical requirements, and hot pressing was the sintering route. Experiments were carried out to study the effects of the sintering temperature on the mechanical properties and microstructure of HfB2-SiC composites with 15 vol% carbon fibres. In this study, the straight carbon fibres became curved during the pressing process, and the reasons were discussed. The mechanical results showed that curved fibres enhanced the fracture properties when the composites were sintered at temperatures below 1900 °C, and the toughening mechanisms, interfacial debonding, crack bridging and pull-out from the matrix were valid. When fibres are employed to improve the fracture toughness of other ceramics, bent fibres might be a common phenomenon, and this paper can provide important guidance to other researchers.