Subcritical crack growth mechanisms in ceramic matrix composites: experimental observations and modelling

Various experimental techniques were used to identify failure mechanisms that occur under occur in continuous fibre-reinforced ceramic matrix composites containing interphases that are susceptible to oxidation. The conditions under which these mechanisms occur were dictated by environmental conditions and microstructural parameters, such as temperature, oxygen concentration, and interphase thickness. Details of the mechanical state of fibres that bridge matrix cracks, during the operation of each mechanism, were developed to allow the application of models that can predict time-dependent, subcritical crack growth. This paper will present evidence of environmentally induced crack growth and discuss a model for predicting the rate of time-dependent, subcritical crack growth.