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Title: Growth and Morphology of Rod Eutectics

Abstract

The formation of rod eutectic microstructure is investigated systematically in a succinonitrile-camphor alloy of eutectic composition by using the directional solidification technique. A new rod eutectic configuration is observed in which the rods form with elliptical cylindrical shape. Two different orientations of the ellipse are observed that differ by a 90{sup o} rotation such that the major and the minor axes are interchanged. Critical experiments in thin samples, where a single layer of rods forms, show that the spacing and orientation of the elliptic rods are governed by the growth rate and the sample thickness. In thicker samples, multi layers of rods form with circular cross-section and the scaling law between the spacing and velocity predicted by the Jackson and Hunt model is validated. A theoretical model is developed for a two-dimensional array of elliptical rods that are arranged in a hexagonal or a square array, and the results are shown to be consistent with the experimental observations. The model of elliptic rods is also shown to reduce to that for the circular rod eutectic when the lengths of the two axes are equal, and to the lamellar eutectic model when one of the axes is much larger than themore » other one.« less

Authors:
; ;
Publication Date:
Research Org.:
Ames Lab., Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
941088
Report Number(s):
IS-J 7327
Journal ID: ISSN 1359-6454; ACMAFD; TRN: US200824%%535
DOE Contract Number:  
DE-AC02-07CH11358
Resource Type:
Journal Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 56; Journal Issue: 12; Journal ID: ISSN 1359-6454
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALLOYS; CONFIGURATION; EUTECTICS; MICROSTRUCTURE; MORPHOLOGY; ORIENTATION; ROTATION; SCALING LAWS; SHAPE; SOLIDIFICATION; THICKNESS; VELOCITY

Citation Formats

Teng, Jing, Liu, Shan, and Trivedi, R. Growth and Morphology of Rod Eutectics. United States: N. p., 2008. Web. doi:10.1016/j.actamat.2008.02.011.
Teng, Jing, Liu, Shan, & Trivedi, R. Growth and Morphology of Rod Eutectics. United States. https://doi.org/10.1016/j.actamat.2008.02.011
Teng, Jing, Liu, Shan, and Trivedi, R. 2008. "Growth and Morphology of Rod Eutectics". United States. https://doi.org/10.1016/j.actamat.2008.02.011.
@article{osti_941088,
title = {Growth and Morphology of Rod Eutectics},
author = {Teng, Jing and Liu, Shan and Trivedi, R},
abstractNote = {The formation of rod eutectic microstructure is investigated systematically in a succinonitrile-camphor alloy of eutectic composition by using the directional solidification technique. A new rod eutectic configuration is observed in which the rods form with elliptical cylindrical shape. Two different orientations of the ellipse are observed that differ by a 90{sup o} rotation such that the major and the minor axes are interchanged. Critical experiments in thin samples, where a single layer of rods forms, show that the spacing and orientation of the elliptic rods are governed by the growth rate and the sample thickness. In thicker samples, multi layers of rods form with circular cross-section and the scaling law between the spacing and velocity predicted by the Jackson and Hunt model is validated. A theoretical model is developed for a two-dimensional array of elliptical rods that are arranged in a hexagonal or a square array, and the results are shown to be consistent with the experimental observations. The model of elliptic rods is also shown to reduce to that for the circular rod eutectic when the lengths of the two axes are equal, and to the lamellar eutectic model when one of the axes is much larger than the other one.},
doi = {10.1016/j.actamat.2008.02.011},
url = {https://www.osti.gov/biblio/941088}, journal = {Acta Materialia},
issn = {1359-6454},
number = 12,
volume = 56,
place = {United States},
year = {Mon Mar 17 00:00:00 EDT 2008},
month = {Mon Mar 17 00:00:00 EDT 2008}
}