Microstructure and mechanical properties of SiC composite ceramics modified by (TixZr1–x)B2 solid solution.

Dense SiC-(Ti x Zr 1–x)B 2 composite ceramics were prepared via solid-state spark plasma sintering (SPS) by controlling the proportion of ZrB 2 (in the range of 5–25 vol%). Through data fitting, a linear functional relationship was established between x and 2θ for the (Ti x Zr 1–x)B 2 solid solution, which rendered it amenable to characterization analysis. The results show that the 2-D morphology of (Ti x Zr 1–x)B 2 tended to transform from angular to round as the ZrB 2 proportion was increased, which was beneficial in crack deflection and increasing the fracture toughness. Moreover, the growth of SiC grains around the solid solution was inhibited, which improved its mechanical properties. The composite ceramic containing 15 vol% of ZrB 2 had the best mechanical properties, with its Vickers hardness, bending strength and fracture toughness reaching 26.12 GPa, 499 MPa, and 6.45 MPa•m1/2, respectively. [ABSTRACT FROM AUTHOR]