The LaB6-(Ti, Zr)B2 composite was fabricated from LaB6, TiB2 and ZrB2 powders by spark plasma sintering (SPS) at 1600–1900°C holding for 5 min under 40 MPa. The densification behaviour, microstructure, mechanical properties were investigated. The complete solid solution phase of (Ti, Zr)B2 was identified. The morphologies of LaB6 and (Ti, Zr)B2 grains were equiaxed and elongated, respectively. The highest relative density of 98.43% and Vickers hardness of 19.56 GPa were obtained at 1900°C. The fracture toughness of 4.43 MPa m1/2 was obtained at 1800°C.
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