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Spinodal decomposition in fine grained materials

Ramanarayan, H and Abinandanan, TA (2003) Spinodal decomposition in fine grained materials. In: Bulletin Of Materials Science, 26 (1). pp. 189-192.

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Abstract

We have used a phase field model to study spinodal decomposition in polycrystalline materials in which the grain size is of the same order of magnitude as the characteristic decomposition wavelength (lambda(SD))In the spirit of phase field models, each grain (i) in our model has an order parameter (eta(i)) associated with it; eta(i) has a value of unity inside the ith grain, decreasessmoothly through the grain boundary region to zero outside the grain. For a symmetric alloy of composition, c = 0.5, our results show that microstructural evolution depends largely on the difference in the grain boundary energies, gamma(gb), of A-rich (alpha) and B-rich (beta) phases. If gamma(gb)(alpha) is lower, we find that the decomposition process is initiated with an a layer being formed at the grain boundary. If the grain size is sufficiently small (about the same as ASD), the interior of the grain is filled with the beta phase. If the grain size is large (say, about 10lambda(SD) or greater), the early stage microstructure exhibits an A-rich grain boundary layer followed by a B-rich layer; the grain interior exhibits a spinodally decomposed microstructure, evolving slowly. Further, grain growth is suppressed completely during the decomposition process.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Indian Academy of Sciences.
Keywords: Spinodal decomposition;grain boundary effects;phase field models.
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 25 Nov 2009 07:45
Last Modified: 19 Sep 2010 04:56
URI: http://eprints.iisc.ernet.in/id/eprint/17367

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