  Within the framework of the lattice-statics and static fluctuation-wave
methods, the available energies of strain-induced interaction of
interstitial-interstitial, interstitial-substitutional and
substitutional-substitutional impurity atomic pairs are collected and analysed
for f.c.c.-(Ni,Fe)-C solutions allowing for discrete atomic structure of the
host-crystal lattice. The lattice spacings, elasticity moduli and/or
quasi-elastic force parameters of the host-crystal lattice, and concentration
coefficients of the dilatation of solid-solution lattice due to the respective
solutes are selected as the input numerical experimental data used. The
above-mentioned interaction energies prove to have non-monotonically decreasing
and anisotropic dependences on discrete interatomic radius-vector, and
themselves are strong and long-range. In all f.c.c.-(Ni,Fe)-base solutions,
there is strain-induced attraction in many coordination shells. In general, the
strain-induced interaction between impurity atoms in gamma-Fe is weaker than in
alpha-Ni. The verification of applicability of the approximation of
strain-induced interaction of impurities for f.c.c.-(Ni,Fe)-C alloys showed
that it must be supplemented with additional short-range (electrochemical)
repulsion in the first coordination shell. Nevertheless, in any case, the
strain-induced interaction of impurity atoms must be taken into account for
analysis of structure and properties of f.c.c.-(Ni,Fe)-base solutions. The
Monte Carlo simulation procedures applied for constitution of a nanoscale
Fe-C-austenite crystallite and based on analysis of the dependences of numbers
of the different atomic configurations on C-C interatomic-interaction energies
reveal correlation between the potential energy of such a modeling system and
the numbers of iterations as well as Monte Carlo steps for the approach to
constrained equilibrium.
