Tensile properties of two-dimensional carbon fiber reinforced silicon carbide composites at temperatures up to 1800 °C in air

Carbon fiber reinforced silicon carbide (C/SiC) composites usually serve in ultra-high-temperature extreme environments and are subjected to thermal-mechanical-oxidation coupled loads. However, the mechanical properties of C/SiC composites reported in the literature are mainly limited to room and moderate temperatures. In this work, the tensile properties of a two-dimensional plain-weave C/SiC composite are studied in air up to 1800 °C for the first time. C/SiC composite shows linear deformation characteristic initially and then strong nonlinear deformation behavior under the tensile load at room temperature. This is because that the initial defects and cracks propagate and result in the interfacial debonding and sliding. The nonlinear deformation behavior decreases as temperature increases because of the reduced thermal residual stresses. The Young's modulus increases up to 1000 °C and then decreases as temperature increases. The tensile strength shows weaker temperature dependence than Young's modulus because that oxidation reduces the strength at elevated temperatures. The failure mechanisms being responsible for the mechanical behavior are gained through macro and micro analysis. The results are useful for the applications of C/SiC composites in the thermal structure engineering.