FEM and experimental research on residual stress, crack propagation and toughening mechanisms of novel bionic ceramic cutting tools

Abstract

To improve the properties of ceramic cutting tools, bionic ceramic cutting tools with innovative interfacial weaves in linear, triangular, square, and wavy shapes were fabricated by bionic design and the bottom-up assembly method. The stress distribution characteristics of the innovative interfacial textures were analyzed by finite element simulation. The effects of stress distribution in the innovative interfacial texture on the crack propagation mechanism were systematically investigated by crack propagation tests and double-sided shear tests, revealing their contribution to fracture resistance. Finally, the effect of residual stress on the properties and interfacial strengthening mechanism of the bionic ceramic cutting tool was evaluated with the microstructure evolution under the modulation of the innovative interfacial texture. The results show that the residual stress can generate a discontinuous stress concentration effect in the peak and valley regions of the innovative interfacial texture. The crack propagation and toughening mechanism can be modulated through stress concentration effects. The interfacial strengthening mechanism indicates that the appropriate and innovative interfacial textures can significantly enhance the mechanical properties and interfacial bonding strength, and further improve the fracture resistance and stability. Furthermore, the formed transition areas can modulate the residual stress distribution and enhance the interfacial bonding strength. The interfacial bonding strengths of linear, triangular, square, and wavy bionic ceramic cutting tools were 63.13 ± 6.4 MPa, 53.25 ± 4.3 MPa, 73.89 ± 8.0 MPa, and 93.26 ± 3.9 MPa, respectively. The wavy bionic ceramic tool exhibits optimal properties in terms of fracture toughness, Vickers hardness, and flexural strength, with values of 7.28 ± 0.27 MPa·m^1/2, 21.53 ± 0.21 GPa, and 912.81 ± 40 MPa, respectively. This work can provide new ideas and methods to improve the properties of bionic ceramic cutting tools.