Flexural properties of carbon-carbon composites at temperatures up to 2600 °C

The flexural properties of carbon-carbon composites (C/Cs) are studied up to 2600 °C for the first time. The results show that the bending strength firstly increases with temperature up to 2000 °C, then decreases moderately to 2300 °C, and finally decreases rapidly to 2600 °C. The temperature dependence of bending strength is related to the bonding strength of the fiber-matrix interface (which increases up to 2000 °C and then decreases with increasing temperature) and the fracture strength of carbon (which increases up to 2300 °C followed by significant reduction as temperature increases). Besides, the study shows that the Young's modulus shows similar temperature dependence with the bending strength, but decreases more rapidly above 2000 °C. Moreover, the deformation behaviors and failure mechanisms at different temperatures are studied. These results are useful for the design, application, and evaluation of the reliability of C/Cs in the thermal structure engineering.