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 deg 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.