Natural convection and columnar-to-equiaxed transition prediction in a front-tracking model of alloy solidification

J. Banaszek, S. McFadden, David J. Browne, L. Sturz, G. Zimmermann

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

A meso-scale front-tracking model (FTM) of nonequilibrium binary alloy dendritic solidification has been extended to incorporate Kurz, Giovanola, and Trivedi (KGT) dendrite kinetics and a Scheil solidification path. Model validation via comparison with thermocouple measurements from a solidification experiment, in which natural convection is limited by design, is presented. Via solution of the flow field due to natural thermal buoyancy, it is shown that resultant liquid-phase convection creates conditions in which equiaxed solidification is favored. Comparison with simulations in which casting solidification is diffusion controlled show that natural convection has greatest effect at intermediate times, but that at early and late stages of columnar solidification, the differences are relatively small. It is, however, during the time of greatest divergence between the simulations that the authors' predictive index for equiaxed zone formation is enhanced most by convection. Finally, the columnar-to-equiaxed transition is directly simulated, in directional solidification controlled by diffusion.

Original languageEnglish
Pages (from-to)1476-1484
Number of pages9
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume38 A
Issue number7
DOIs
Publication statusPublished - 1 Jul 2007

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