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

Hybrid C-f 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 C-f-SiCf-(Al2O3p)/KGP composites were investigated. Results showed that the amorphous matrix of C-f-SiCf-(Al2O3p)/KGP composites transformed into kalsilite and leucite phase after treated at 1000 and 1200 degrees 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 degrees C. All the composites showed a non-catastrophic fracture behavior after heat treated, which was attributed to fiber pulling-out and debonding. (C) 2017 Elsevier Ltd. All rights reserved.