Tensile properties of three-dimensional stitched C/C composites prepared from different precursor materials at temperatures up to 2500 ℃

Three-dimensional stitched C/C composites are promising for ultra-high-temperature aerospace applications. This work investigates the tensile properties and failure mechanisms of C/C composites prepared from phenolic resin and coal tar pitch at temperatures up to 2500 °C. Results show that coal tar pitch-based C/C composites exhibit a tensile strength of 178.7 MPa at 2500 °C, higher than the resin-carbon-based composites. XRD illustrates that due to higher matrix graphitization in the former. As the temperature rises from room temperature to 2000 °C, the tensile strength of coal tar pitch-based composites increases from 191.4 MPa to 216.2 MPa, but decreases to 178.7 MPa at 2500 °C due to the accumulation of thermal residual stress. Large cracks and interface debonding are observed by SEM. Resin-carbon-based composites show minor tensile strength loss under different holding times. These findings provide insights into the use of C/C composites in thermal structures.