Effect of Chopped Carbon Fiber on Mechanical Properties of ZrB2-SiC Composite

In this research, effect of carbon fiber (Cf) and its content on sinter-ability, hardness and fracture toughness of ZrB2-SiC composites which were produced by spark plasma sintering, was studied. For this purpose, four composites with different Cf content (10, 20, 30 and 40 vol%) were sintered by spark plasms at 1800 °C, 40 MPa pressure for 6 minutes by with a heating rate of ~50 °C/min. In order to evaluate the microstructure, scanning electron microscopy, EDS and x-ray diffraction was applied. The hardness and fracture toughness were measured by macro-Vickers and SENB method, respectively. In this research, Cf addition does not have any significant effect on hardness. The results showed by increasing Cf, relative density decreases and open porosity percent increases. Fracture toughness of ZrB2-SiC composites was improved by increasing Cf content.