Modelling environmental effects on stress oxidation behaviour of carbon fibre reinforced ceramic matrix composites

AbstractA model has been developed for describing the stress oxidation strain evolution of carbon silicon carbide (C/SiC) composite in thermal, mechanical and chemical applied environments. A failure criterion is proposed to predict the lives of the C/SiC composites. The life is dominated by carbon phase oxidation if coat and matrix cracks are open to allow oxygen ingress. Crack opening displacement δ is considered as a key microstructural governing parameter and determined by the combination of mechanical and thermal expansion mismatch induced stresses, i.e. increased stresses widen the δ and increased temperatures narrow the δ. The proposed model gave correct and reliable prediction.Keywords: CARBON FIBRECERAMIC MATRIX COMPOSITESENVIRONMENTAL DEGRADATIONANALYTICAL MODELLING