Effects of high-temperature heat treatment on the microstructure and mechanical performance of hybrid Cf-SiCf-(Al2O3p) reinforced geopolymer composites

Hybrid Cf and SiCf reinforced geopolymer composites with Al2O3 particles were successfully fabricated, and the effects of high-temperature treatment on the microstructure evolution and mechanical properties of Cf-SiCf-(Al2O3p)/KGP composites were investigated. Results showed that the amorphous matrix of Cf-SiCf-(Al2O3p)/KGP composites transformed into kalsilite and leucite phase after treated at 1000 and 1200 °C, respectively, due to the addition of fibers hindering crystallization of the geopolymer matrix. The addition of Al2O3p was helpful to increase the thermal stability of composites after high-temperature treatment. Flexural strength and Young's modulus of the composites decreased after high temperature treatment and showed the maximum values at 1000 °C. All the composites showed a non-catastrophic fracture behavior after heat treated, which was attributed to fiber pulling-out and debonding.