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Influence of yttria and zirconia additions on spark plasma sintering of alumina composites

Chakravarty, Dibyendu and Chokshi, Atul H (2015) Influence of yttria and zirconia additions on spark plasma sintering of alumina composites. In: JOURNAL OF MATERIALS RESEARCH, 30 (8). pp. 1148-1156.

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Official URL: http://dx.doi.org/ 10.1557/jmr.2015.72

Abstract

The mechanisms of densification and creep were examined during spark plasma sintering (SPS) of alumina doped with a low and high level of zirconia or yttria, over a temperature range of 1173-1573 K and stresses between 25 and 100 MPa. Large additions of yttria led clearly to in situ reactions during SPS and the formation of a yttrium-aluminum garnet phase. Dopants generally lead to a reduction in the densification rate, with substantial reductions noted in samples with similar to 5.5 vol% second phase. In contrast to a stress exponent of n similar to 1 for pure alumina, the doped aluminas displayed n similar to 2 corresponding to an interface-controlled diffusion process. The higher activation energies in the composites are consistent with previous data on creep and changes in the interfacial energies. The results reveal a compensation effect, such that an increase in the activation energy is accompanied by a corresponding increase in the pre-exponential term for diffusion.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the CAMBRIDGE UNIV PRESS, 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Depositing User: Id for Latest eprints
Date Deposited: 26 Jun 2015 07:32
Last Modified: 26 Jun 2015 07:32
URI: http://eprints.iisc.ac.in/id/eprint/51782

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