High-temperature fatigue behavior of SiC-coated carbon/carbon composites in oxidizing atmosphere

Tensile fatigue-stressed oxidation experiments were conducted at 1300 °C in oxidizing atmosphere to identify the failure modes and degradation mechanism of a SiC-coated carbon/carbon composite. Five peak fatigue stresses were selected between 90 and 150 MPa and the results showed that the higher the applied stress, the shorter the composite life. Electrical resistance of the composite was acquired in real-time. The composite resistance appeared a slight drop in the initial fatigue period and followed by a continuous increase until failure. Both the changes in modulus and resistance revealed the shrinking core mechanism in the fatigue-stressed oxidation experiments. A model was developed based on a half-cylinder oxidation pattern. Simulations were conducted on the basis of this model, and the results agreed with the experimental data fairly well.