DYNAMIC FRACTURE OF CERAMICS AND CERAMIC COMPOSITES

The dynamic fracture responses of alumina (Al2O3), TiB2 particulate-SiC matrix and SiC whisker (SiCw)-Al2O3 matrix ceramic composites are presented in the context of dynamic fracture mechanics where a dynamic arrest stress intensity factor (SIF) did not exist in these brittle materials. Fractography study of the Al2O3 specimens showed that the area of transgranular failures increased from about 3% to about 16% under rapid crack extensions in statically and impact-loaded specimens respectively. Thus the continuing crack propagation at low SIF was attributed to increasing transgranular failure due to the kinematic constraints imposed by flat crack extension. The fracture process zone was also identified as the dominant energy dissipation mechanism in SiCw-Al2O3 ceramic matrix composite.