Microstructure and mechanical properties of ZrB2-SiC nanocomposite ceramic

A ZrB2-SiC nanocomposite ceramic in which 20 vol.% nanosized SiC powder was introduced into a ZrB2 matrix was fabricated by hot-pressing at 1900 degrees C for 60 min under a 30 MPa uniaxed load. The composite microstructure showed intragranular nanostructures that were peculiar to this material. Investigation of the mechanical properties revealed a flexural strength of 930 +/- 28 MPa and a fracture toughness of 6.5 +/- 0.3 MPa m(1/2). These improved mechanical properties were strongly dependent on the formation of the unusual intragranular nanostructures. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.