Fabrication and mechanical properties of ZrB2-SiCw ceramic matrix composite

A ZrB2 based ceramic matrix composite containing 20 vol.% Sic whisker was fabricated at 1800 degrees C for 1 h under a uniaxial load of 40 MPa by hot-pressing. The microstructure and mechanical properties of the composite were investigated. It was shown that mechanical properties were improved by introduction of Sic whisker, especially for the fracture toughness. The fracture toughness was similar to 5.97 +/- 0.3 MPa m(0.5), which was much higher than that of monolithic ZrB2 and SiC particle reinforced ZrB2 Composite. The toughening mechanisms were Whisker bridging, crack deflection around whiskers as well as whisker pull-out and fracture. The results presented here point to a potential method for improving fracture toughness of ultra-high temperature ceramic. (c) 2007 Elsevier B.V. All rights reserved.