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Nanoscale compositional changes along fast ion tracks in equilibrium solid solutions: A computer simulation of ultra-fast solidification and thermomigration

Published online by Cambridge University Press:  15 March 2011

Edmundo M. Lopasso
Affiliation:
Centro Atómico Bariloche - Instituto Balseiro, 8400 Bariloche, Argentina
Alfredo Caro
Affiliation:
Centro Atómico Bariloche - Instituto Balseiro, 8400 Bariloche, Argentina
Eduardo Ogando Arregui
Affiliation:
Dep. de Electricidad y Electrónica, UPV-EHU apdo. 644, 48080 Bilbao, España
Magdalena Caro
Affiliation:
Centro Atómico Bariloche - Instituto Balseiro, 8400 Bariloche, Argentina
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Abstract

Starting from two equilibrium solid solutions in the Au-Ni system, we analyze the change in composition due to a 400 eV/Å fast ion track simulated by molecular dynamics in the Embedded Atom approximation. We aim at determining the influence of the thermodynamic forces derived from the large thermal gradients and the rapid solidification across the solidus and liquidus on the motion of solute atoms. One dimensional gradients as well as analytic models are used to quantitatively determine the domains of influence of these forces. Evidence shows that the liquidus and solidus equilibrium solidification predicted by the phase diagram is not reached during the track. The solute concentration is mainly determined by the combined diffusion and thermomigration mechanisms in the liquid stage.

Type
Research Article
Copyright
Copyright © Materials Research Society 2002

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References

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