MODELING OF CRACK PROMGATION BEHMIOR IN WHISKER REINFORCED CERAMIC COMPOSITES
晶须增韧陶瓷基复合材料裂纹扩展行为模型

The crack propagation behavior in whisker reinforced ceramic composites is described analytically by establishing the R-curve equation that involves two toughening mechanisms, crack bridging and crack deflection. The equation is used to calculate the R-curves and Load-displacement curves Of some kinds of Al2O3/SiCw composites, which exhibited effective whisker toughening. The calculated results indicate that the repeated crack propagation, followed by crack arrest behavior is caused by crack bridging mechanism; With the increase of whisker content, the two toughening mechanisms toughening effects are all increased, and the dominant toughening mechanism changed gradually from crack deflection to crack bridging; The whisker toughening effect will be lost when whiskers are tend to parallel the main crack plane. Predictions of fracture toughness based on the present model are shown to be in good agreement with experimental results.