Microstructure and mechanical properties of ZrB2–SiC–ZrO2f ceramic

ZrB2–SiC–ZrO2f ceramic was fabricated by hot-pressing at 1850 °C for 1 h under a uniaxial load of 30 MPa in vacuum. The ZrB2–SiC–ZrO2f ceramic thus produced showed excellent fracture toughness due to the addition of ZrO2 fiber. The increase in toughness was attributed mainly to the addition of the ZrO2 fiber, which could enhance fiber pull-out, crack bridging and crack branching. In addition, the stress-induced transformation toughening was also considered to be main reason for the improvement in toughness.

Research highlights
► Zirconia fiber was used as reinforcing phase.
► The flexural strength and fracture toughness were obviously increased.
► Toughening mechanisms are transformation toughening, fiber pull-out, bridging and branching.