Effect of thermo-mechanical and low-cycle preloading on the strength of carbon fiber-reinforced ceramic matrix composites

Fiber-reinforced ceramic matrix composites (CMCs) exhibit excellent thermo-mechanical properties including outstanding resistance against damage and fatigue. Some CMCs show occasionally even a strength enhancement after fatigue, often interpreted with relieve of internal stresses and interfacial degradation. This study reports the influence of low-cycle thermo-mechanical preloading on the bending and tensile strength of carbon fiber-reinforced silicon carbon (C/C-SiC). For this purpose two C/C-SiC materials with the same fiber architecture but different assumed internal stress states were subjected to single and cyclic mechanical preloads up to 90% of their ultimate strength level at room temperature and at 350 degrees C. Statistical evaluations of the experiments show that the ultimate strength values were surprisingly unchanged after preloading. The results are discussed regarding the thermal residual stresses (TRS).

Automated summary

The influence of low-cycle thermo-mechanical preloading on the strength of carbon fiber-reinforced silicon carbon (C/C-SiC) was experimentally investigated. The results show that the ultimate strength values of C/C-SiC were not significantly changed after preloading.