Preparation and mechanical properties of laminated B4C-TiB2/BN ceramics

Laminated B4C-TiB2 ceramics with h-BN interface layers were successfully prepared by roll forming and tape casting, and samples with different numbers of stacked layers were obtained. Scanning electron microscopy and X-ray diffraction were used to analyze the microstructure and interlayer crystal phases of the composites, and the bending strength, fracture toughness, and work of fracture were measured. As the number of h-BN layers increased, the fracture toughness increased from 7.38 +/- 0.5 MPa m(1/2) to 9.01 +/- 0.61 MPa m(1/2), which is 2-3 times higher than that of monolithic B4C ceramics. As the fracture toughness increased, the hardness remained at a high level (31.67 GPa). Bending tests showed that cracks deflected when they encountered the h-BN interfacial layers. The toughening mechanisms included the deflection and branching of cracks and generation of new microcracks, which increased the length of the propagation path and work of fracture.

Automated summary

Laminated B4C-TiB2 ceramics with h-BN interface layers were successfully prepared using roll forming and tape casting techniques. Increasing the number of h-BN layers can effectively enhance the fracture toughness of the ceramics, resulting in significantly improved performance compared to monolithic B4C ceramics.