Interactions between columnar solidification and segregation: a comparison of the predictions of the CAFE model with in-situ observations
Résumé
A two-dimensional (2D) cellular automaton (CA) - finite element (FE) model has been proposed to simulate the solidification of binary alloys. The time evolution of maps of temperature, composition and fraction of solid are simulated while accounting for the undercooling of the growing structure. The solidification experiment of a Gallium-5wt%Indium alloy developed by Yin and Koster [1-2] is shown to provide a good benchmark for comparison with predictions of the model. Observed and simulated time evolutions of the development of the grain structure and the macrosegregation can be directly compared, together with mesosegregation such as segregated channels. These channels differ from freckle-type segregation described in the literature. They form as a result of the dynamics of the columnar growth front and its interaction with the fluid and solute flows. Comparisons of the predictions of the CAFE model with a purely macroscopic FE model also reveal the influence of accounting for the growth undercooling in numerical modeling of solidification.
Domaines
Matériaux
Origine : Fichiers produits par l'(les) auteur(s)
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