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Is there diffusion creep in alumina?

Kottada, RS and Chokshi, AH (2000) Is there diffusion creep in alumina? In: Creep and Fracture of Engineering Materials and Structures - CFEMS-8, 1-5 Nov. 1999, Tsukuba, Japan, pp. 779-786.

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Abstract

Although early studies on polycrystalline alumina attributed creep to diffusional processes, a re-analysis of the data and additional experimental results indicated that the creep behavior was non-linear, with a stress exponent of n~2, where ε˙$\alpha \sigma^n$ and ε˙ and σ are the strain rate and stress, respectively. Recently, there has been renewed interest in characterizing the mechanical properties of alumina-based ceramics, in view of the possibility of obtaining superplastic-like large elongations in such materials. However, the occurrence of concurrent grain growth and extensive cavitation has precluded a complete characterization of the mechanisms of tensile flow. This paper reviews some of the earlier studies, and then describes results from recent experimental results on alumina doped with 300 ppm magnesia. The mechanical testing was accompanied by detailed microstructural investigations on grain growth, changes in grain shape and cavitation. These experimental results and appropriate analysis are used to critically examine the possibility of diffusion creep in polycrystalline alumina

Item Type: Conference Paper
Additional Information: Copyright of this article belongs to Trans Tech Publications
Keywords: alumina;diffusion creep;grain growth;grain size;impurities;magnesium compounds;plastic flow;slip;superplasticity;voids solid
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 06 Aug 2007
Last Modified: 27 Aug 2008 12:43
URI: http://eprints.iisc.ernet.in/id/eprint/10376

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