Formation of Eutectic Cells in Ternary Al‐Cu‐Ag Alloys

Hecht, U.; Witusiewicz, V.T.; Drevermann, Anne; Rex, S.

doi:10.1002/3527603506.ch28

Cited by 8 publications

(9 citation statements)

References 10 publications

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“…Fig. 12a through d depicts the solutal configuration obtained at the planar eutectic interface in the ternary alloy Al-Cu 15.52 at.%-Ag 9.04 at.% after unidirectional solidification and subsequent quenching of the bulk sample according to Hecht et al [102]. Qualitatively this configuration is similar to what is known from the single-phase solidification of a binary alloy with a planar solid/liquid interface, which of course is also univariant.…”

Section: Coupled Growth and Morphological Stability Of Univariant Eutmentioning

confidence: 56%

“…In bulk samples, additional phenomena arise from the 3D nature of the eutectic and the cellular pattern: Based on unidirectional solidification experiments with different Al-Cu-Ag alloys with Ag concentration ranging from 4 to 10 at.% Hecht et al [102] argued that the primary instability of an initially planar eutectic interface consisting of a(Al) and Al 2 Cu lamellae occurred within the plane of the lamellae rather than in direction perpendicular to the lamellae.…”

Section: Coupled Growth and Morphological Stability Of Univariant Eutmentioning

confidence: 99%

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Multiphase solidification in multicomponent alloys

Hecht

Gránásy

Pusztai

et al. 2004

Materials Science and Engineering: R: Reports

167

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Section: Coupled Growth and Morphological Stability Of Univariant Eutmentioning

confidence: 56%

Section: Coupled Growth and Morphological Stability Of Univariant Eutmentioning

confidence: 99%

Multiphase solidification in multicomponent alloys

Hecht

Gránásy

Pusztai

et al. 2004

Materials Science and Engineering: R: Reports

167

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“…The second type of anisotropy function that we will study is motivated by the observation of strong locking of growth directions onto certain crystallographic planes. This usually occurs when the two solid phases exhibit an epitaxial orientation relationship [19]. In this case, the locking planes correspond to sharp cusplike minima in the yap{9) function.…”

Section: B Anisotropic Interphase Boundariesmentioning

confidence: 99%

“…On the one hand, in floa tin g (eutectic) grains, the dynam ics o f the lam ellar solidification front patterns is w ell described by the standard theory o f regular eutectics. In particular, spatial inhom ogeneities o f the lam ellar spacing are sm oothed out w ith tim e by a "spacing-diffusion" process [8,9] generically present in out-of-equilibrium pattern-form ing system s [18], On the other hand, in locked grains, eutectic lam ellae grow in a direction that is essentially aligned to a certain crystallographic plane and are inclined (or tilted) w ith respect to the main grow th axis z [17,19]. The strength o f this crystallographic locking effect varies betw een different eutectic grains.…”

Section: Introductionmentioning

confidence: 99%

Interphase anisotropy effects on lamellar eutectics: A numerical study

et al. 2015

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In directional solidification of binary eutectics, it is often observed that two-phase lamellar growth patterns grow tilted with respect to the direction z of the imposed temperature gradient. This crystallographic effect depends on the orientation of the two crystal phases α and β with respect to z. Recently, an approximate theory was formulated that predicts the lamellar tilt angle as a function of the anisotropy of the free energy of the solid(α)-solid(β) interphase boundary. We use two different numerical methods-phase field (PF) and dynamic boundary integral (BI)-to simulate the growth of steady periodic patterns in two dimensions as a function of the angle θ(R) between z and a reference crystallographic axis for a fixed relative orientation of α and β crystals, that is, for a given anisotropy function (Wulff plot) of the interphase boundary. For Wulff plots without unstable interphase-boundary orientations, the two simulation methods are in excellent agreement with each other and confirm the general validity of the previously proposed theory. In addition, a crystallographic "locking" of the lamellae onto a facet plane is well reproduced in the simulations. When unstable orientations are present in the Wulff plot, it is expected that two distinct values of the tilt angle can appear for the same crystal orientation over a finite θ(R) range. This bistable behavior, which has been observed experimentally, is well reproduced by BI simulations but not by the PF model. Possible reasons for this discrepancy are discussed.

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“…The full success of this "isotropic" theory in suitably chosen eutectic grains [3,4,5] should not eclipse the importance of crystallographic effects linked to interphase boundary anisotropy in other eutectic grains. Numerous metallic eutectics, notably Al-Al 2 Cu [6] or Al-Al 2 Cu-based ternary eutectics [7], form "epitaxial" eutectic grains (i.e. eutectic grains with orientation relationships between phases such that there exists low-energy orientations for the interphase boundary) upon directional solidification [8].…”

Section: Introductionmentioning

confidence: 99%

A theory of thin lamellar eutectic growth with anisotropic interphase boundaries

Akamatsu

Bottin-Rousseau²,

Şerefoğlu³

et al. 2012

Acta Materialia

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To cite this version:S Akamatsu, S Bottin-Rousseau, M Serefog˘lu, G Faivre. A theory of thin lamellar eutectic growth with anisotropic interphase boundaries. Acta Materialia, Elsevier, 2012, 60, pp.3199 -3205. 10.1016/j.actamat.2012 Rotating-I-esub3We present a semiempirical theory of the effects of an orientation dependence of the surface free energy of interphase boundaries (interphase boundary anisotropy) on lamellar eutectic growth in thin samples. We show that, to a good approximation, thin lamellar eutectic patterns with a strong interphase boundary anisotropy travel along the growth front at such a velocity -or, equivalently, at such an inclination angle of the lamellae left behind in the solid -that the surface tension force of the interphase boundary is nearly parallel to the applied thermal gradient. This explains, among other things, the crystallographic locking of lamellar eutectic patterns that occurs in those eutectic grains, which have cusp singularities in the Wulff plot of the interphase boundary. Based on this theory, we show that the rotating directional solidication (RDS) method, by which a thin sample is rotated with respect to a fixed unidirectional thermal gradient, must yield eutectic lamellae whose trajectories are nearly homothetic to the 2D Wulff form of the interphase boundary. This opens up new possibilities for the experimental study of interphase boundary anisotropy in eutectic alloys.

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Formation of Eutectic Cells in Ternary Al‐Cu‐Ag Alloys

Cited by 8 publications

References 10 publications

Multiphase solidification in multicomponent alloys

Multiphase solidification in multicomponent alloys

Interphase anisotropy effects on lamellar eutectics: A numerical study

A theory of thin lamellar eutectic growth with anisotropic interphase boundaries

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