Article

# On the role of confinement on solidification in pure materials and binary alloys

07/2006; DOI:10.1080/14786430500157060
Source: arXiv

ABSTRACT We use a phase-field model to study the effect of confinement on dendritic growth, in a pure material solidifying in an undercooled melt, and in the directional solidification of a dilute binary alloy. Specifically, we observe the effect of varying the vertical domain extent ($\delta$) on tip selection, by quantifying the dendrite tip velocity and curvature as a function of $\delta$, and other process parameters. As $\delta$ decreases, we find that the operating state of the dendrite tips becomes significantly affected by the presence of finite boundaries. For particular boundary conditions, we observe a switching of the growth state from 3-D to 2-D at very small $\delta$, in both the pure material and alloy. We demonstrate that results from the alloy model compare favorably with those from an experimental study investigating this effect.

0 0
·
0 Bookmarks
·
50 Views
• ##### Article: Modeling the interaction of biological cells with a solidifying interface
[hide abstract]
ABSTRACT: In this article, we develop a modified level set method for modeling the interaction of particles with a solidifying interface. The dynamic computation of the van der Waals and drag forces between the particles and the solidification front leads to a problem of multiple length scales, which we resolve using adaptive grid techniques. We present a variety of example problems to demonstrate the accuracy and utility of the method. We also use the model to interpret experimental results obtained using directional solidification in a cryomicroscope.
Journal of Computational Physics 01/2007; · 2.14 Impact Factor
• ##### Article: The Growth of a Single Cell/Dendrite in a Directional Solidification Process
[hide abstract]
ABSTRACT: Following the original model for a single cell/dendrite growth by Hunt,[5] systematic numerical simulations are carried out with focus on cell shape evolution and tip radius selection in a directional solidification process conducted in a capillary tube. Computations indicate that the anisotropy of solid/liquid interfacial energy and the diameter of a capillary tube have significant influences on the selection of a tip shape. The anisotropy in dilute SCN-salol alloys has been determined through the equilibrium droplet shape method and its value is 1.09 pct. The calculated cell/dendrite shapes with this value of anisotropy agree with experimental observations where a single cell/dendrite of SCN-salol alloys grows in a capillary tube.
Metallurgical and Materials Transactions A 06/2007; 38(7):1378-1387. · 1.63 Impact Factor