Dynamics of Low Anisotropy Morphologies in Directional Solidification
Abstract
We report experimental results on quasi-two-dimensional diffusion limited growth in directionally solidified succinonitrile with small amounts of poly(ethylene oxide), acetone, or camphor as a solute. Seaweed growth, or dense branching morphology, is selected by growing grains close to the plane, where the in-plane surface tension is nearly isotropic. The observed growth morphologies are very sensitive to small anisotropies in surface tension caused by misorientations from the plane. Different seaweed morphologies are found, including the degenerate, the stabilized, and the strongly tilted seaweeds. The degenerate seaweeds show a limited fractal scaling range and, with increased undercooling, suggests a transition from "fractal" to "compact" seaweed. Strongly tilted seaweeds demonstrate a significant twofold anisotropy. In addition, seaweed-dendrite transitions are observed in low anisotropy growth.
Keywords
Cite
@article{arxiv.cond-mat/0206179,
title = {Dynamics of Low Anisotropy Morphologies in Directional Solidification},
author = {B. Utter and E. Bodenschatz},
journal= {arXiv preprint arXiv:cond-mat/0206179},
year = {2009}
}
Comments
12 pages, 17 figures, submitted to Phys. Rev. E, reduced image quality for smaller file size