M. Hagen et Mw. Finnis, POINT-DEFECTS AND CHEMICAL-POTENTIALS IN ORDERED ALLOYS, Philosophical magazine. A. Physics of condensed matter. Structure, defects and mechanical properties, 77(2), 1998, pp. 447-464
We discuss the thermodynamics of point defects in an ordered A(m)B(n)
alloy for small deviations from the stoichiometric composition. The co
ncentrations of the two kinds of antisite and vacancy are functions of
three basic energies of formation and of the stoichiometry. We derive
general formulae for them which can be solved numerically. Analytic f
ormulae for the chemical potentials are derived in terms of the point-
defect concentrations. Simple analytic formulae are derived for the co
ncentrations which are valid when the constitutional defects (which do
minate at low temperatures) continue to dominate the thermally excited
defects of the same type at higher temperatures. The energies enterin
g these formulae are defined in a general way, suitable for ab initio
or semiempirical methods of calculation. We illustrate the results wit
h calculations for NiAl using three different central N-body potential
s. A significant effect is due to the temperature dependence of the fo
rmation energies.