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Structure of Grain Boundaries in L12 Alloys at Finite Temperatures: Effects of Deviations from Stoichiometry

Published online by Cambridge University Press:  25 February 2011

M. Yan ,
V. Vitek  and
G. J. Ackland
M. Yan
Affiliation:
Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104–6272, U. S. A.
V. Vitek
Affiliation:
Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104–6272, U. S. A.
G. J. Ackland
Affiliation:
Department of Physics, University of Edinburgh, Edinburgh, Scotland, U. K.
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Abstract

Atomic structures of grain boundaries in Ni3Al and Cu3Au has been studied using a Monte Carlo relaxation technique and many body central force potentials to describe interatomic forces. The purpose of this work is to investigate the temperature dependence of the compositional order in the boundary region for both stoichiometric and non-stoichiometric alloys. In the former case the boundaries in Ni3Al remain ordered up to very high temperatures while boundaries in Ni3Al disorder at relatively low temperatures. In the non-stoichiometric case, the surplus of nickel in the bulk leads to segregation to grain boundaries and to a significant chemical disordering in the boundary region. The surplus of aluminum also leads to segregation but without disordering in the boundary region. Using these results we discuss the intrinsic brittleness of grain boundaries in Ni3Al as well as the effect of stoichiometry on the intergranular brittleness.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 238: Symposium Cb – Structure and Properties of Interfaces in Materials , 1991 , 139
Copyright
Copyright © Materials Research Society 1992

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References

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