Effects of high-temperature annealing on the microstructure and properties of C/ZrC composites prepared by reactive melt infiltration

Abstract

C/ZrC composites prepared by reactive melt infiltration at 1900°C contained ~4.2vol% residual α-Zr which was harmful to the high-temperature mechanical properties and ablation resistance. Thus, the composites were heat-treated for 1h from 1200°C to 2000°C. The residual α-Zr amount was only 0.6vol% after annealing at 2000°C, indicating that high temperature promoted the diffusion and reaction of Zr and C to consume α-Zr. C/ZrC composites had the optimum flexural properties of 192MPa and 17.7GPa after annealing at 1600°C. The ablation resistance was improved after high-temperature annealing, and the mass loss rate and linear recession rate decreased as the temperature increased, which were 0.0021g/s and 0.0008mm/s respectively after annealing at 2000°C.