Fracture Toughness Modeling and Toughening Mechanisms Taking Into Account Grain Growth and Crack Deflections of Bionic Ceramic Cutting Tool Materials

ABSTRACT A theoretical model of fracture toughness for bionic ceramic cutting tools was established by bionic design of the macro and micro toughening mechanisms of shells. This model can guide and optimize the fabrication process based on the required fracture toughness. Then, by prefabricating the macro‐strong physical bonding interface, the effect laws of compositions and structural parameters on the theoretical model of fracture toughness and the toughening mechanism are obtained. The results show that the interface strengthening effect is gradually enhanced with the decrease of layer thickness ratio and the increase of the number of layers. The synergistic effects of multiple crack deflections, interfacial strengthening mechanisms (residual stress toughening and stepped fracture) and nanoparticle toughening improve the mechanical properties of bionic ceramic cutting tools. This theoretical model offers an advanced design concept and functional application for laminated materials.