High-temperature effects on the compressive behaviors of SiC-coated carbon-bonded carbon fiber composites: Insights into mechanical properties and cyclic deformation recovery

Porous SiC-coated carbon-bonded carbon fiber composites (SiC-coated CBCFs) are fabricated via chemical vapor deposition (CVD) method, where silicon carbide coatings are uniformly applied to carbon fibers bonded by pyrolytic carbon while preserving their three-dimensional interconnected pore structure. The mechanical responses of SiC-coated CBCFs under elevated temperatures are systematically characterized through quasi-static compression testing coupled with multiscale microstructural analysis. The results demonstrate a monotonic decrease in elastic moduli as temperature increases to 2000 °C. In contrast, compressive strengths initially rise and then experience a slight fluctuation before the significant decrease. Under stepwise cyclic compressive loading, both the deformation recovery ability and load-bearing stiffness exhibit notable degradation at elevated temperatures, highlighting the need for larger safety margins in realistic thermal insulation scenarios. These findings establish quantitative correlations between thermomechanical degradation mechanisms and operational limits, offering valuable insights for their design and application in reusable high-performance systems.