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A Comparison of the Surface Composition of Solid and Liquid Alloys

Published online by Cambridge University Press:  25 February 2011

J. A. Barnard
Affiliation:
Carnegie-Mellon University, Dept. of Metallurgical Engineering and Materials Science, Pittsburgh, PA 15213
P. Wynblatt
Affiliation:
Carnegie-Mellon University, Dept. of Metallurgical Engineering and Materials Science, Pittsburgh, PA 15213
William C. Johnson
Affiliation:
Carnegie-Mellon University, Dept. of Metallurgical Engineering and Materials Science, Pittsburgh, PA 15213
W.W. Mullins
Affiliation:
Carnegie-Mellon University, Dept. of Metallurgical Engineering and Materials Science, Pittsburgh, PA 15213
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Abstract

The surface compositions of three In-Pb alloys (1.42a/o Pb, 3.07a/o Pb, and 5.86a/o Pb) have been obtained as a function of temperature in both solid and liquid states using a scanning Auger microprobe. All data were obtained at temperature, from equilibrated samples in a region of about fifty degrees on either side of the liquidus temperature. Lead was found to be the segregating component in all cases. From these measurements, the heat of segregation has been calculated for all alloys in both states. In each alloy the magnitude of the heat of segregation declines significantly on melting although the absolute surface compositions are found to be continuous across the two phase solid-liquid field. These results are interpreted in the light of current segregation theories. Particular attention is paid to the role of elastic effects on solute segregation to free surfaces.

Type
Research Article
Copyright
Copyright © Materials Research Society 1987

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References

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