Grain boundary effects on spinodal decomposition II. Discontinuous microstructures

Ramanarayan, H and Abinandanan, TA (2004) Grain boundary effects on spinodal decomposition II. Discontinuous microstructures. In: Acta Materialia, 52 (4). pp. 921-930.

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Abstract

We have used a phase field model of a polycrystalline alloy, presented in [Acta Mater. 51 (2003) 4761], to study the effect of enhanced atomic mobility at the grain boundary (GB) on spinodal decomposition (SD) in two dimensional systems. For sufficiently large values of atomic mobility at the GB $(M_g),$ and of GB mobility $(L_g),$ fast decomposition along the boundary converts it into a transformation front, whose migration leaves behind a discontinuous microstructure consisting of alternating A-rich and B-rich lamellae. We present a theory of discontinuous SD under the assumption of a small degree of decomposition in the lamellae (i.e., large values of $L_g/M_g).$ In this limit, for a given $M_g,$ increasing $L_g$ leads to a decrease in the degree of decomposition in the lamellae, but does not alter the lamellar spacing and front velocity, which remain constant. The results from our simulations are in good agreement with these theoretical predictions.

Item Type:	Journal Article
Publication:	Acta Materialia
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Spinodal decomposition;Grain boundaries;Discontinuous transformation;Phase field models
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	30 May 2006
Last Modified:	22 Feb 2012 08:20
URI:	http://eprints.iisc.ac.in/id/eprint/7086

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