Effects of whisker content and dimensions on theR-curve behavior of an alumina matrix composite reinforced with silicon carbide whiskers

A study was made of the effects of whisker content and dimensions on theR-curve behavior of an alumina matrix composite reinforced with silicon carbide whiskers. Experiments showed that the risingR-curve behavior is strongly enhanced by the increase in the volume fraction and the size of whiskers. Simulation based on a model of crack face whisker bridgings was made to elucidate the effects on theR-curve of the composite. The validity of the simulation was confirmed by good agreement between the experimental and the calculatedR-curves. In addition to theR-curve, the distribution of crack closure stresses as well as crack tip opening displacements was also calculated, which directly reflects crack face whisker bridging processes in the composite. Then the dependence of whisker content and dimensions on theR-curve was analytically discussed taking the bridging processes into account.