Abstract
We present the results of a numerical study based on the boundary integral technique of interfacial pattern formation in directional solidification of thin-film lamellar eutectics at low velocity. Microstructure selection maps that identify the stability domains of various steady-state and nonsteady-state growth morphologies in the spacing-composition (λ –C 0) plane are constructed for the transparent organic alloy CBr4-C2Cl6 and for a model eutectic alloy with two solid phases of identical physical properties. In CBr4-C2Cl6, the basic set of instabilities that limit steady-state growth is richer than expected. It consists of three primary instabilities, two of which are oscillatory, which bound the domain of the commonly observed axisymmetric lamellar morphology, and two secondary oscillatory instabilities, which bound the domain of the nonaxisymmetric (tilted) lamellar morphology. The latter is predicted to occur over a hypereutectic range of composition which coincides well with experiment. Moreover, the steady tilt bifurcation lies between but does not directly bound either of these two domains, which are consequentlydisjoint. Four stable oscillatory microstructures, at least three of which have been seen experimentally, are predicted to occur in unstable regimes. In the model alloy, the structure is qualitatively similar, except that a stable domain of tilted steady-state growth is not found, in agreement with previous random-walk simulations. Furthermore, the composition range of stability of the axisymmetric morphology decreases sharply with increasing spacing away from minimum undercooling but extends further off-eutectic than predicted by the competitive growth criterion. In addition, oscillations with a wavelength equal to two λ lead to lamella termination at a small distance above the onset of instability. The implications of these two features for the eutectic to dendrite transition are examined with the conclusion that in the absence of heterogeneous nucleation, this transition should be histeritic at small velocity and temperature gradient.
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References
W.H. Brandt:J. Appl. Phys., 1945, vol. 16, p. 139.
C. Zener:Trans. TMS-AIME, 1946, vol. 167, p. 550.
W.A. Tiller:Liquid Metals and Solidification, ASM, Cleveland, OH, 1958, p. 276.
M. Hillert:Jernkontorets Ann., 1957, vol. 141, p. 773.
K.A. Jackson and J.D. Hunt:Trans. TMS-AIME, 1966, vol. 236, p. 1129.
F.R. Mollard and M.C. Flemings:Trans. TMS-AIME, 1967, vol. 239, p. 1534.
H.E. Cline:Trans. TMS-AIME, 1968, vol. 242, p. 1613.
W.W. Mullins and R.F. Sekerka:J. Appl. Phys., 1963, vol. 34, p. 323.
D.T.J. Hurle and E. Jakeman:J. Cryst. Growth, 1968, vol. 3(4), p. 574.
J.D. Hunt, D.T.J. Hurle, K.A. Jackson, and E.J. Jakeman:Trans. AIME, 1970, vol. 1, p. 381.
S. Strassler and W.R. Schneider:Phys. Cond. Matter, 1974, vol. 17, p. 153.
H.E. Cline:J. Appl. Phys., 1979, vol. 50, p. 4780.
V. Datye and J.S. Langer:Phys. Rev., 1981, vol. B24, p. 4155; J.S. Langer:Phys. Rev. Lett., 1980, vol. 44, p. 1023.
This assumption is often credited to Cahn (unpublished) who argued on its basis that spacings smaller than λm should be unstable.
An analysis by B. Caroli, C. Caroli, and B. Roulet(J. Phys. (France), 1990, vol. 51, p. 1865) has indicated that the critical spacing for this instability should not be expected to coincide with λm in the limit of large thermal gradient. It is not presently (rigorously) known by how much the two spacings differ in the experimentally relevant range of growth conditions where this gradient is much weaker than assumed in their analysis.
M. Zimmermann, A. Karma, and M. Carrard:Phys. Rev., 1990, vol. B42, p. 833.
S.C. Gill and W. Kurz:Acta Metall. Mater., 1993, vol. 41, p. 3563.
B. Caroli, C. Caroli, G. Faivre, and J. Mergy:J. Cryst. Growth, 1992, vol. 118, p. 135.
J. Mergy: Ph.D. Thesis, Université Paris 7, Paris, 1992; also J. Mergy, G. Faivre, C. Guthmann, and R. Mellet:J. Cryst. Growth, 1993, vol. 134, p. 353.
A. Karma:Phys. Rev. Lett., 1987, vol. 59, p. 71.
A. Karma: inSolidification Processing of Eutectic Alloys, D.M. Stefanescu, G.J. Abbaschian, and R.J. Bayuzick, eds., TMS, Cincinnati, OH, 1988, p. 35; alsoPrinciples of Solidification and Materials Processing, R. Trivedi, J.A. Sekhar, and J. Mazumdar, eds., Oxford, New Delhi, Bombay, and IBH Publishing Co., Calcutta, India, 1989, vol. 1, p. 243.
K. Kassner and C. Misbah:Phys. Rev., 1991, vol. A44, p. 6533.
B. Caroli, C. Caroli, and S. Fauve:J. Phys. I (France), 1992, vol. 2, p. 281.
C. Misbah and D.E. Temkin:Phys. Rev., 1992, vol. A46, p. R4497.
A. Valence, C. Misbah, D. Temkin, and K. Kassner:Phys. Rev., 1993, vol. E48, p. 1924.
G. Faivre, S. De Cheveigne, C. Guthman, and P. Kurowski:Europhys. Lett., 1989, vol. 9, p. 779.
G. Faivre and J. Mergy:Phys. Rev., 1992, vol. A45, p. 7320;Phys. Rev., 1992, vol. A46, p. 963.
R.-F. Xiao, J.I.D. Alexander, and F. Rosenberger:Phys. Rev., 1992, vol. A45, p. R571;Mater. Sci. Eng., 1994, vol. A178, p. 233.
B.A. Wolfe Diesslin and W.T. Grayhack:Phys. Rev., 1994, vol. B50, p. 9111.
For a review of this approach with reference to the earlier literature, see W. Kurz and D.J. Fisher:Int. Met. Rev., 1979, vol. 177; also R. Trivedi and W. Kurz: inSolidification Processing of Eutectic Alloys, D.M. Stefanescu, G.J. Abbaschian, and R.J. Bayuzick, eds., TMS, Cincinnati, OH, 1988, pp. 3–34.
G.E. Nash:J. Cryst. Growth, 1977, vol. 38, p. 155.
D.A. Kessler and H. Levine:J. Cryst. Growth, 1989, vol. 94, p. 871.
K. Kassner and C. Misbah:Phys. Rev., 1991, vol. A44, p. 6513.
A. Karma:Phys. Rev., 1994, vol. E49, p. 2245.
A.A. Wheeler, G.B. McFadden, and W.J. Boettinger: National Institute of Technology, Gaithersburg, MD 20899,Proceedings of the Royal Society of London, 1994.
K.R. Elder, F. Drolet, J.M. Kosterlitz, and M. Grant:Phys. Rev. Lett, 1994, vol. 72, p. 677.
A. Sarkissian: Ph.D. Thesis, Northeastern University, Boston, MA, 1994.
J.D. Hunt and K.A. Jackson:Trans. TMS-AIME, 1966, vol. 236, p. 843.
W.F. Kaukler and J. Rutter:Mater. Sci. Eng., 1984, vol. 65, p. LI.
V. Seetharaman and R. Trivedi:Metall. Trans. A, 1988, vol. 19A, pp. 2955–64.
C. Caroli and G. Faivre:Solid State Communications, in press.
A. Karma:Phys. Rev., 1986, vol. A34, p. 4353.
M. Ginibre: Ph.D. Thesis, Université Paris 7, Paris, in preparation.
J.D. Verhoeven and E.D. Gibson:Metall Trans., 1972, vol. 3, pp. 1893–98.
J.D. Verhoeven and E.D. Gibson:Metall. Trans., 1973, vol. 4, pp. 2581–90.
K.A. Jackson:Trans. TMS-AIME, 1968, vol. 242, p. 1275.
G. Faivre and M. Ginibre: Groupe de Physique des Solides, Université Paris VII, Paris, private communication, 1994.
T.F. Bower, H.D. Brody, and M.C. Flemings:Trans. TMS-AIME, 1966, vol. 236, p. 624.
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This article is based on a presentation made at the “Analysis and Modeling of Solidification” symposium as part of the 1994 Fall meeting of TMS in Rosemont, Illinois, October 2–6, 1994, under the auspices of the TMS Solidification Committee.
Formerly Postgraduate Student, Physics Department, Northeastern University
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Karma, A., Sarkissian, A. Morphological instabilities of lamellar eutectics. Metall Mater Trans A 27, 635–656 (1996). https://doi.org/10.1007/BF02648952
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DOI: https://doi.org/10.1007/BF02648952