Effect of growth rates and temperature gradients on the spacing and undercooling in the broken-lamellar eutectic growth (Sn-Zn eutectic system)
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Date
2003
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Journal Title
Journal ISSN
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Publisher
ASM INTERNATIONAL
Access Rights
info:eu-repo/semantics/closedAccess
Abstract
The Sn-Zn system has a eutectic structure of a broken lamellar type. Dependence of the broken-lamellar spacing lambda and the undercooling DeltaT on V and G were investigated, and the relationship between them was examined. A Sn-Zn (99.99%) high-purity eutectic alloy was melted in a graphite crucible under vacuum atmosphere. This eutectic alloy was directionally solidified upward with a constant growth rate V (8.30 mum/s) and different temperature gradients G (1.86-6.52 K/mm), and also with a constant temperature gradient (6.52 K/mm) and different growth rates (8.30-165.13 mum/s) in a Bridgman-type directional solidification furnace. The lamellar spacings lambda were measured from both transverse and longitudinal sections of the specimen. The lambda values from the transverse section were used for calculations and comparisons with the previous works. The undercooling values DeltaT were obtained using growth rate and system parameters K-1 and K-2. It was found that the values of lambda decreased while V and G increased. The relationships between lamellar spacing lambda and solidification parameters V and G were obtained by linear regression analysis method. The lambda(2)V, DeltaTlambda, DeltaTV(-0.5), and lambda(3)G values were determined using lambda, DeltaT, V, and G values. The experimentally obtained values for the broken-lamellar growth (Sn-Zn eutectic system) were in good agreement with the theoretical and other experimental values.
Description
Keywords
broken-lamellar growth, directional solidification, eutectic alloys, lamellar spacings, Sn-Zn eutectic alloys, undercooling, microstructure
Journal or Series
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
WoS Q Value
Q4
Scopus Q Value
Q2
Volume
12
Issue
4
