Authors: Supriyo Ghosh Mathis Plapp
Publish Date: 2015/10/07
Volume: 68, Issue: 6, Pages: 1235-1238
Abstract
It is well documented in many experiments that crystallographic effects play an important role in the generation of twophase patterns during the solidification of eutectic alloys In particular in lamellar composites large patches of perfectly aligned lamellae are frequently observed Moreover the growth direction of the lamellae often markedly differs from the direction of the temperature gradient the lamellae are tilted with respect to the main growth direction Both of these effects cannot be explained either by the standard theory or the available numerical models of eutectic growth which all assume the interfaces to be isotropic We have developed a phasefield model in which the anisotropy of each interface solid–liquid and solid–solid can be separately controlled and we have investigated the effect of interface anisotropy on the growth dynamics We have found that anisotropy of the solid–solid interphase boundary free energy dramatically alters the growth dynamics Tilted lamellae resulting from the modified equilibrium condition at the triple lines is in good agreement with a theoretical conjecture proposed recently In three dimensions the interphase boundaries tend to align with directions of minimal energy We have also performed simulations in which two grains with different anisotropies are in competition In all cases the grain containing the boundaries with the lowest energies was selected after a transient These results shed new light on the selection of growth patterns in eutectic solidification
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