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Evolution of multivariant microstructures with anisotropic misfit: A phase field study

Bhattacharyya, Saswata and Abinandanan, TA (2009) Evolution of multivariant microstructures with anisotropic misfit: A phase field study. In: Acta Materialia, 57 (3). pp. 646-656.

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Official URL: http://dx.doi.org/10.1016/j.actamat.2008.10.008

Abstract

We study, in two dimensions, the effect of misfit anisotropy on microstructural evolution during precipitation of an ordered beta phase from a disordered alpha matrix; these phases have, respectively, 2- and 6-fold rotation symmetries. Thus, precipitation produces three orientational variants of beta phase particles, and they have an anisotropic (and crystallographically equivalent) misfit strain with the matrix. The anisotropy in misfit is characterized using a parameter t = epsilon(yy)/epsilon(xx), where epsilon(xx) and epsilon(yy) are the principal components of the misfit strain tensor. Our phase field, simulations show that the morphology of beta phase particles is significantly influenced by 1, the level of misfit anisotropy. Particles are circular in systems with dilatational misfit (t = 1), elongated along the direction of lower principal misfit when 0 < t < 1 and elongated along the invariant direction when - 1 <= t <= 0. In the special case of a pure shear misfit strain (t = - 1), the microstructure exhibits star, wedge and checkerboard patterns; these microstructural features are in agreement with those in Ti-Al-Nb alloys.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier Science.
Keywords: Phase field models;Microstructure;Phase transformations; Precipitation;Coarsening.
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Depositing User: Rajalaxmi Ashok Govanakoppa
Date Deposited: 01 May 2009 04:56
Last Modified: 22 Feb 2012 08:41
URI: http://eprints.iisc.ac.in/id/eprint/19210

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