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Title: On dendritic solidification of multicomponent alloys with unequal liquid diffusion coefficients

Abstract

A model has been developed previously by Rappaz and Thevoz (Acta metall, 1987, 35, 1478; 1987, 35, 2929) for the solidification of binary alloys having an equiaxed dendritic morphology. The extension of this model to multicomponent alloys is straightforward if the diffusion coefficients in the liquid of the various solute elements are equal. When they are different however, it becomes necessary to distinguish the concentrations at the dendrite tip position, governing the growth kinetics, from the average concentrations within the interdendritic liquid region. A model is presented which couples the dendrite growth kinetics with an overall solute balance performed at the scale of the grain. The diffusion profile outside the grain envelope is calculated using a Landau transformation and an implicit scheme. The calculated solidification paths during and after recalescence are compared with the Scheil approximation for various conditions. Additionally, a model predicting the secondary dendrite arm spacing in multicomponent alloys is briefly described.

Authors:
 [1];  [2]
  1. Ecole Polytechnique Federale de Lausanne (Switzerland). Lab. de Metallurgie Physique
  2. National Inst. of Standards and Technology, Gaithersburg, MD (United States). Metallurgy Div.
Publication Date:
OSTI Identifier:
684380
Resource Type:
Journal Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 47; Journal Issue: 11; Other Information: PBD: 8 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; SOLIDIFICATION; ALLOYS; LIQUID METALS; MATHEMATICAL MODELS; DENDRITES; KINETICS; DIFFUSION

Citation Formats

Rappaz, M., and Boettinger, W.J. On dendritic solidification of multicomponent alloys with unequal liquid diffusion coefficients. United States: N. p., 1999. Web. doi:10.1016/S1359-6454(99)00188-3.
Rappaz, M., & Boettinger, W.J. On dendritic solidification of multicomponent alloys with unequal liquid diffusion coefficients. United States. doi:10.1016/S1359-6454(99)00188-3.
Rappaz, M., and Boettinger, W.J. Wed . "On dendritic solidification of multicomponent alloys with unequal liquid diffusion coefficients". United States. doi:10.1016/S1359-6454(99)00188-3.
@article{osti_684380,
title = {On dendritic solidification of multicomponent alloys with unequal liquid diffusion coefficients},
author = {Rappaz, M. and Boettinger, W.J.},
abstractNote = {A model has been developed previously by Rappaz and Thevoz (Acta metall, 1987, 35, 1478; 1987, 35, 2929) for the solidification of binary alloys having an equiaxed dendritic morphology. The extension of this model to multicomponent alloys is straightforward if the diffusion coefficients in the liquid of the various solute elements are equal. When they are different however, it becomes necessary to distinguish the concentrations at the dendrite tip position, governing the growth kinetics, from the average concentrations within the interdendritic liquid region. A model is presented which couples the dendrite growth kinetics with an overall solute balance performed at the scale of the grain. The diffusion profile outside the grain envelope is calculated using a Landau transformation and an implicit scheme. The calculated solidification paths during and after recalescence are compared with the Scheil approximation for various conditions. Additionally, a model predicting the secondary dendrite arm spacing in multicomponent alloys is briefly described.},
doi = {10.1016/S1359-6454(99)00188-3},
journal = {Acta Materialia},
number = 11,
volume = 47,
place = {United States},
year = {1999},
month = {9}
}