Effect of SiCnws on flexural strength of SiCf/HfC-SiC composites after impact and ablation.

• SiC f /HfC-SiC and SiC nws modified SiC f /HfC-SiC composites were prepared by PIP and CVI methods. • SiC nws were helpful to increase the pyrolysis yield rate of HfC precursor. • After impact-ablation, the flexural strength of SiC f /HfC-SiC reduced by 45.2 %; that of modified one only reduced by 30.9 %. SiC nanowires (SiC nws) modified SiC f /HfC-SiC composites were prepared by precursor infiltration and pyrolysis (PIP) and chemical vapor infiltration (CVI) methods. The microstructure, flexural strengths, impact and impact-ablation tests of the composites with and without SiC nws were investigated. The results showed that after introducing SiC nws , not only the retention rate of HfC ceramic produced by PIP was increased obviously, but also the fracture displacement of the modified composites was reduced due to the enhancement effect of SiC nws at interface between SiC fiber and matrix. After impact and impact-ablation, the strength retention of SiC nws modified composites was 91.6 % and 69.1 % respectively, higher than that of the composites without SiC nws (85.2 % and 54.8 %). As the impact resistance of the modified composites was improved by the pull-out and bridging of SiC nws , the ablation resistance of the impacted composites was enhanced as well. [ABSTRACT FROM AUTHOR]