Influence of ceramic-metal interface adhesion on crack growth resistance of ZrO2-Nb ceramic matrix composites

Yttria-stabilized zirconia strengthened with lamellar flaky-shape Nb metal particles was obtained by hot-pressing at 1500 degrees C for 1 h. The ZrO2-Nb interface has been studied by atomistic, first-principles calculations and by high-resolution transmission electron microscopy. The influence of the ceramic-metal interface on the crack growth resistance has been investigated. Crack growth is shown to occur with a rising resistance, governed by intact metal ligaments in the crack wake. Crack extension occurs by a combination of plastic deformation on the metal particles and interface debonding. The connection between the interface adhesion and this microstructural toughening mechanism has been evaluated. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.