Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Pb-2.2 wt pct Sb and Pb-5.8 wt pet Sb alloys have been directionally solidified from a single-crystal seed with its  orientation parallel to the growth direction, to examine the primary dendrite distribution and disorder of the dendrite arrays. The dendrite distribution and ordering have been investigated using analysis techniques such as the Gauss-amplitude fit to the frequency distribution of nearest and higher-order spacings, minimum spanning tree (MST), Voronoi polygon, and Fourier transform (FT) of the dendrite centers. Since the arrangement of dendrites is driven by the requirement to accommodate side-branch growth along the (100) directions, the FT images of the fully developed dendrite centers contain spots which indicate this preferred alignment. A directional solidification distance of about three mushy-zone lengths is sufficient to ensure a steady-state dendritic array, in terms of reaching a constant mean primary spacing. However, local dendrite ordering continues throughout the directional solidification process. The interdendritic convection not only decreases the mean primary spacing, it also makes the dendrite array more disordered and reduces the ratio of the upper and lower spacing limits, as defined by the largest 5 pct and the smallest 5 pct of the population.
Hui, Jun; Tiwari, R.; Wu, X.; Tewari, Surendra N.; and Trivedi, R., "Primary Dendrite Distribution and Disorder During Directional Solidification of Pb-Sb Alloys" (2002). Chemical & Biomedical Engineering Faculty Publications. 17.
Hui, J., Tiwari, R., Wu, X., Tewari, S.N., & Trivedi, R. (2002). Primary Dendrite Distribution and Disorder During Directional Solidification of Pb-Sb Alloys. Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science 33, 3499-3510.
Copyright 2002 ASM International. This paper was published in Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 33, Issue 11, pp. 3499-3510 and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.
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