Hertzian crack analysis in alumina–chromium composites

• Published in: Journal of the European Ceramic Society 2005-05, Vol.25 (7), p.1119-1132
• Main Authors: Geandier, G., Denis, S., Hazotte, A., Mocellin, A.
• Format: Article
• Language: English
• Subjects: Al 2O 3/Cr; Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Ceramic Matrix Composite; Cermets, ceramic and refractory composites; Chemical industry and chemicals; Chemical Sciences; Condensed Matter; Condensed matter: structure, mechanical and thermal properties; Cristallography; Cross-disciplinary physics: materials science; rheology; Engineering Sciences; Exact sciences and technology; Fatigue, brittleness, fracture, and cracks; Fracture toughness; Hertz crack; Materials Science; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Mechanics; Mechanics of materials; Microstructure; Miscellaneous; Other materials; Physics; Specific materials; Technical ceramics
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2004.04.022

Ceramic metal composites are of interest for their good resistance to crack propagation. We have prepared different kinds of alumina chromium composites, observed their microstructures and made an analysis of Hertzian cracks in order to identify the principle parameters of crack propagation in relation with the metallic phase size and distribution in the matrix. The crack is analysed at two scales, a macroscopic one to estimate the fracture toughness from the overall crack and a microscopic one to study, at the local level, the influence of the metallic phase on crack propagation. Using macroscopic models the fracture toughness estimation highlights the benefit of the presence of chromium particles. Observations and measurements made on the crack path and metallic phase, from the microstructure analysis, combined with the knowledge of the residual stress state, provide the principal parameters governing crack propagation in these composites.