Effect of graphite flake orientation on microstructure and mechanical properties of ZrB_2-SiC-graphite composite

摘要

ZrB_2-20 vol percent SiC ultrahigh temperature ceramics matrix composite was hot-pressed at 1900 deg C doped with the 15 vol percent graphite flake (ZrB_2-SiC-graphite). It was found that the addition of the graphite flake promoted the grain refining and densification of the ZrB_2-SiC-graphite composite. The effect of the graphite flake orientation on microstructure and mechanical properties of the ZrB_2 -SiC-graphite composite was investigated. The results revealed the anisotropy in the flexural strength and fracture toughness of the ZrB_2 -SiC-graphite composite. In contrast to the flexural strength and fracture toughness, the hardness of the ZrB_2-SiC-graphite composite did not show significant anisotropy.