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Phase Stability of the Sigma Phase in Fe-Cr Based Alloys

Published online by Cambridge University Press:  10 February 2011

Marcel Il. F ,
Sluiter. Koivan Esfurjani  and
Yoshiyuki Kawazoe
Marcel Il. F
Affiliation:
Institute for Materials Research, Tohoku University., Sendai 980-77, Japan
Sluiter. Koivan Esfurjani
Affiliation:
Institute for Materials Research, Tohoku University., Sendai 980-77, Japan
Yoshiyuki Kawazoe
Affiliation:
Institute for Materials Research, Tohoku University., Sendai 980-77, Japan
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Abstract

The FeCr sigma phase is a good example of a complex structure: it. has 30 atoms in the unit cell and 5 inequivalent lattice sites, and it belongs to the class of tetrahedrally close packed structures, also known as Frank-Kaspar structures. So far. such structures have riot been treated within a first-principles statistical thermodynamics framework. It will be shown that dtlme to advances in algorithms and hardware important features of the phase stability of complex phases can be computed. The factors which affect the stability of the sigma phase have been studied using carefully selected supercells for electronic total energy calculations. cluster variation calc:ulations in the tet.rahedron approximation were performed to evaluate the effect of partial disorder and of finite temperature. The preferred occupancy of the 5 lattice sites has been investigated and is compared with experimental determinations.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 408: Symposium P – Materials Theory, Simulations, and Parallel Algorithms , 1995 , 369
Copyright
Copyright © Materials Research Society 1996

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References

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