Buoyancy effects of a growing, isolated dendrite

D. Canright*, S. H. Davis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

An axisymmetric dendrite of pure material solidifies downward into an undercooled melt. Surface energy and kinetic undercooling are negligible. The Ivantsov [Dokl. Akad. Nauk SSSR 58 (1947) 567] parabolic dendrite is modified by buoyant convection. We construct an approximate solution to the growth/convection problem in powers of a buoyancy parameter G. The solution depends on Prandtl number P and Stefan number S (undercooling). When P and/or S are large enough, buoyancy enhances growth and distorts the dendrite by sharpening the tip and widening the base. These results compare well with the experiments on succinonitrile (P = 23) of Huang and Glicksman [Acta Met. 29 (1981) 701] and the local theory of Ananth and Gill [J. Crystal Growth 91 (1988) 587] up to G ≈ 1000, but overpredict convective effects for larger G. When P and S are small enough, buoyancy slows growth and flattens the tip. Physical explanations are given for the differences in buoyant effects at different P. The results suggest that near-tip effects of buoyancy should be different in metallics than in organics.

Original languageEnglish (US)
Pages (from-to)153-185
Number of pages33
JournalJournal of Crystal Growth
Volume114
Issue number1-2
DOIs
StatePublished - Oct 1991

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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