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Calculation of The Diffusion Parameters in an Ordered Ni3Al-Alloy for A Relaxed Lattice

Published online by Cambridge University Press:  10 February 2011

C. Schmidt
Affiliation:
Section de Recherches de Métallurgie Physique, CEA-Saclay, 91191 Gif-sur-Yvette, France, schmidt@srmp101.saclay.cea.fr
J.L. Bocquet
Affiliation:
Section de Recherches de Métallurgie Physique, CEA-Saclay, 91191 Gif-sur-Yvette, France
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Abstract

Using atomistic computer simulations, we calculate the diffusion parameters of an Ll2-ordered Ni3Al-alloy. A conjugate gradient algorithm under constant zero pressure and a semi-empirical N-body potential are applied to evaluate potential barrier heights and pre-exponential factors. We focus our investigation on those diffusion mechanisms that have been proposed to account for the experimentally observed but theoretically still disputed fast self-diffusion of Al in Ni3Al: antisite bridge mechanisms and correlated six-jump cycles. Our results demonstrate that the most competitive jumps or jump sequences involve AlNJ-antistructure atoms which are shown to play a key role in the diffusion process by either actively or passively lowering the activation energy of migration.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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