TIME-DEPENDENT CRACK GROWTH IN CERAMIC COMPOSITES: FROM SINGLE FIBERS TO BRIDGED CRACKS

摘要

Several failure mechanisms, dictated by environmental conditions, temperature, interphase thickness, etc. occur in continuous fiber-reinforced ceramic matrix composites containing interphases that are susceptible to oxidation. Experimental techniques have been used to identify these mechanisms and conditions under which they occur. Details of the mechanical state of fibers that bridge matrix cracks, during the operation of each mechanism, are required to allow the application of models that can predict time-dependent, subcritical crack growth. This paper will present evidence of environmentally induced failure and discuss a simple method, using the compliance of individual fibers, for describing the stress state of fibers that bridge matrix cracks.