Effect of SiC nanowires on the mechanical properties and thermal conductivity of 3D-SiCf/SiC composites prepared via precursor infiltration pyrolysis

In this study, SiC nanowires (SiCNWS) were grown in situ on the surface of PyC interface through chemical vapor infiltration (CVI) to improve the mechanical characteristics and thermal conductivity of three-dimensional SiCf/SiC composites fabricated via precursor infiltration pyrolysis (PIP). The effect of SiCNWS on the properties of the obtained composites was investigated by comparing them with conventional SiCf/PyC/SiC composites. After the deposition of SiCNWS, the flexural strength of the SiCf/SiC composites was found to increase by 46 %, and the thermal conductivity showed an obvious increase at 25-1000 degrees C. The energy release of the composites in the damage evolution process was analysed by acoustic emission. The results indicated that the damage evolution process was delayed owing to the decrease in porosity, the crack deflection and bridging of the SiCNWS. Furthermore, the excellent thermal conductivity was attributed to the thermally conductive pathways formed by the SiCNWS in the dense structure.

Automated summary

In this study, SiC nanowires (SiCNWS) were grown on the surface of PyC interface via chemical vapor infiltration (CVI) to enhance the mechanical characteristics and thermal conductivity of three-dimensional SiCf/SiC composites. The presence of SiCNWS resulted in a 46% increase in flexural strength and significant enhancement of thermal conductivity in the temperature range of 25-1000 degrees C. Analysis of energy release during damage evolution process revealed delayed damage evolution due to decreased porosity, crack deflection, and bridging of SiCNWS. The excellent thermal conductivity was attributed to thermally conductive pathways formed by SiCNWS in the dense structure.