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Kinetic paths of B2 and DO3 order parameters: Theory

Published online by Cambridge University Press:  31 January 2011

L. Anthony  and
B. Fultz
L. Anthony
Affiliation:
Department of Materials Science 138–78, California Institute of Technology, Pasadena, California 91125
B. Fultz
Affiliation:
Department of Materials Science 138–78, California Institute of Technology, Pasadena, California 91125
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Abstract

It is shown that a binary alloy with an AB3 stoichiometry on a bcc lattice may develop various combinations of B2 and DO3 order along its kinetic path toward equilibrium. The temporal evolution of these two order parameters is analyzed with an activated-state rate theory. Individual vacancy jumps are treated in a master equation formalism that involves first-nearest-neighbor (1nn) and second-nearest-neighbor (2nn) interactions. In our formulation, a set of coupled differential equations is obtained describing the time-dependence of six order parameters. These equations were integrated numerically for a variety of interatomic interactions and initial conditions. It was found that the relative rates of B2 and DO3 ordering, and hence the path of the alloy through the space spanned by the B2 and DO3 order parameters, depend on the relative strengths of the interatomic interaction potentials and on the temperature. For very strong 2nn interactions, a transient B32 structure was observed to develop at early times, although this phase disappeared as equilibrium was approached.

Type
Articles
Information
Journal of Materials Research , Volume 4 , Issue 5 , October 1989 , pp. 1132 - 1139
Copyright
Copyright © Materials Research Society 1989

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References

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