CYCLIC FATIGUE OF A SINTERED AL2O3 ZRO2 CERAMIC/

A systematic experimental and theoretical study on the crack growth be haviour of a sintered Al2O3/ZrO2 ceramic under cyclic loading is prese nted. It is found that in the cyclic fatigue experiments conducted on the single-edge-notched beam (SENB) geometry, for similar testing cond itions, the crack growth rates are significantly faster than those und er static fatigue. Al2O3/ZrO2 therefore suffers genuine mechanical fat igue. Further experiments with the compact tension (CT) geometry show that the mechanical fatigue effect arises mainly from the degradation of the bridging mechanism. A theoretical analysis based on the complia nce technique and a power law relationship between the crack-wake brid ging stress and the crack-face separation is developed to evaluate qua ntitatively the degradation of the bridging stress due to cyclic fatig ue.