Study on microstructures and mechanical properties of short-carbon-fiber-reinforced SiC composites prepared by hot-pressing

Abstract

Short-carbon-fiber-reinforced silicon carbide composites were prepared by hot-pressing with SiC powder, Polycarbosilane as precursor polymer and MgO–Al 2O 3–Y 2O 3 as sintering additives. The phase composition, microstructure and mechanical properties of the composites with different Polycarbosilane content were investigated. The results showed that, dense composites could be prepared at a relatively low temperature of 1800 °C via the liquid-phase-sintering mechanism and the highest mechanical property was obtained for the composites with 20 wt.% PCS and 8 wt.% sintering additives. The amorphous interphase formed during sintering process in the composites not only contributed to the densification of the composites, but also improved the fiber–matrix bonding. The nano-silicon carbide derived from Polycarbosilane, could also play a role of improving the relative density of the composites.