Toughening Mechanisms of Al_2O_3/TiC Ceramic Composite with Carbon Additive

With carbon as an additive, the fracture toughness of Al2O3/TiC ceramic material fabricated by hot pressing technology is increased by 20% than that of Al2O3/TiC composite without any carbon added. The results of theoretical and experimental analyses show that the existing of weak interfaces in the ceramic material is one of the effective approaches to achieve higher fracture toughness. The added carbon, existing as a form of graphite, can result in not only the formation of spontaneous microcracks but also the formation of weak interfaces. As a result of the comprehensive integration and synergism of varieties of single toughening mechanisms such as crack bridging, crack branching and crack defection etc., the fracture toughness of Al2O3/TiC ceramic material can be enhanced obviously.