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Evolution of defect size and strength of porous alumina during sintering

Flinn, Brian D. and Bordia, Rajendra K. and Zimmermann, André and Rödel, Jürgen (2000):
Evolution of defect size and strength of porous alumina during sintering.
In: Journal of the European Ceramic Society, pp. 2561-2568, 20, (14-15), ISSN 0955-2219, [Online-Edition: http://dx.doi.org/10.1016/S0955-2219(00)00133-3],
[Article]

Abstract

The evolution of fracture strength with increasing density in ceramics, using alumina as a model system, is discussed in terms of the interplay between a defect serving as stress concentrator, a crack lying in its enhanced stress field and the fracture toughness of the porous ceramic. Introduction of crack-free fracture-causing artificial pores of various sizes allows detailed measurement of their shrinkage with ongoing densification, while fractography describes the location and type of fracture initiation. A fracture mechanics model, describing growth of a semicircular crack emanating from the pore until instability, yields good agreement with experiment. In particular, the result that the radius of the artificial, spherical defect in a size regime between 25 and 120 mum has only a small influence on fracture strength for samples with an average grain size smaller than 1 mum, can be explained. (C) 2000 Elsevier Science Ltd. All rights reserved.

Item Type: Article
Erschienen: 2000
Creators: Flinn, Brian D. and Bordia, Rajendra K. and Zimmermann, André and Rödel, Jürgen
Title: Evolution of defect size and strength of porous alumina during sintering
Language: English
Abstract:

The evolution of fracture strength with increasing density in ceramics, using alumina as a model system, is discussed in terms of the interplay between a defect serving as stress concentrator, a crack lying in its enhanced stress field and the fracture toughness of the porous ceramic. Introduction of crack-free fracture-causing artificial pores of various sizes allows detailed measurement of their shrinkage with ongoing densification, while fractography describes the location and type of fracture initiation. A fracture mechanics model, describing growth of a semicircular crack emanating from the pore until instability, yields good agreement with experiment. In particular, the result that the radius of the artificial, spherical defect in a size regime between 25 and 120 mum has only a small influence on fracture strength for samples with an average grain size smaller than 1 mum, can be explained. (C) 2000 Elsevier Science Ltd. All rights reserved.

Journal or Publication Title: Journal of the European Ceramic Society
Volume: 20
Number: 14-15
Uncontrolled Keywords: Al2O3; crack growth; mechanical properties; porosity; sintering; GRAIN-SIZE; FRACTURE; PORES; CERAMICS; BEHAVIOR; MODULUS
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 14 Jul 2011 11:25
Official URL: http://dx.doi.org/10.1016/S0955-2219(00)00133-3
Identification Number: doi:10.1016/S0955-2219(00)00133-3
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