Microsegregation in Peltier Interface Demarcation

Published

July 1, 2000

Author(s)

Y Dabo, H N. Thi, Sam R. Coriell, Geoffrey B. McFadden, Q Li, B Billia

Abstract

Experimental results on solute microsegregation induced by Peltier Interface Demarcation (PID) technique during directional solidification of Bi-1 wt % Sb alloys are presented. These data are compared with the results of numerical simulation and the theory of PID is revisited. It is shown that the Peltier coefficient previously determined using Peltier pulsing has been underestimated. The quantity of interface cooling absorbed by limited Bi-growth kinetics is comparable to that covered by solute depletion, and can even be dominant for very short pulses, so that the commonly made assumption of local equilibrium at the solid-liquid interface (i.e. usual hypothesis of constant interface temperature during pulse marking for pure systems) should be abandoned and the right dependence of interface temperature on solidification velocity be included in the model. Finally, two conditions to select systems capable of efficient marking by PID microsegregation are deduced and the effects of applied current in the first instants of electric pulse clarified.

Citation

Journal of Crystal Growth

Volume

216

Issue

No. 1-4

Pub Type

Journals

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Keywords

alloy solidification, bismuth-antimony alloys, interface demarcation, microsegregation, Peltier pulsing

Citation

Dabo, Y. , Thi, H. , Coriell, S. , McFadden, G. , Li, Q. and Billia, B. (2000), Microsegregation in Peltier Interface Demarcation, Journal of Crystal Growth, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=150779 (Accessed May 16, 2024)