Design of alumina-zirconia composites with spatially tailored strength and toughness. Issue 2 (February 2015)

• Record Type: Journal Article
• Authors: Chang, Yunfei; Bermejo, Raul; Ševeček, Oldřich; Messing, Gary L.
• Is Part Of: Journal of the European Ceramic Society. Volume 35:Issue 2(2015:Feb.)
• Page Start: 631
• Page End: 640
• Publication Date: 2015-02
• Subjects: Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2014.09.017
• Languages: English
• ISSNs: 0955-2219

Abstract

<abstract abstract-type="author" id="abs0005"> <title id="sect0005">Abstract</title> <sec> <p id="spar0005">Composites of Al<sub>2</sub>O<sub>3</sub>–5 vol.% <italic>t</italic>-ZrO<sub>2</sub> (ATZ) and Al<sub>2</sub>O<sub>3</sub>–30 vol.% <italic>m</italic>-ZrO<sub>2</sub> (AMZ) layers were designed with 3–1 connectivity to explore the effect of spatially-dependent residual stress and layer distribution on mechanical behavior. ATZ composites with 'shallow' and 'deep' regions of AMZ, defined relative to the distance from the surface, were fabricated. Four-point bending tests on indented 3–1 composites showed crack arrest in the first compressive AMZ layer and a fracture strength nearly independent of indent size (i.e. minimum strength); the failure occurring in the region with thicker outer ATZ layers ('deep' region). Region dependent crack growth resistance was measured on SEVNB specimens and compared to theoretical predictions using a fracture mechanics model. Spatially tailored constant strengths were obtained, ranging between 148 MPa and 470 MPa; the maximum value corresponding to a 'shallow' region with a relatively thicker AMZ compressive layer embedded close to the tensile ATZ surface. The 3–1 design concept allows the fabrication of 'deep' and 'shallow' embedded regions within a unique composite architecture, thus providing a preferential path for crack propagation, opening new possibilities for design of composite structures with spatially-tailored crack growth resistance.</p> </sec> </abstract>