Effect of graphite flake orientation on microstructure and mechanical properties of ZrB2–SiC–graphite composite

ZrB2–20 vol% SiC ultrahigh temperature ceramics matrix composite was hot-pressed at 1900 °C doped with the 15 vol% graphite flake (ZrB2–SiC–graphite). It was found that the addition of the graphite flake promoted the grain refining and densification of the ZrB2–SiC–graphite composite. The effect of the graphite flake orientation on microstructure and mechanical properties of the ZrB2–SiC–graphite composite was investigated. The results revealed the anisotropy in the flexural strength and fracture toughness of the ZrB2–SiC–graphite composite. In contrast to the flexural strength and fracture toughness, the hardness of the ZrB2–SiC–graphite composite did not show significant anisotropy.