Interaction between the carbon atoms in FeC austenite was studied usin
g the experimental data; of Mossbauer spectroscopy giving the abundanc
es of the iron sites with different carbon neighbourhoods and Monte Ca
rlo computer simulation with CC pair interaction parameters which coul
d result in carbon distribution satisfying the experimental data. The
values of the carbon activity in FeC austenite were also derived from
CC interaction parameters and compared with the experimental data avai
lable, which, in turn, allowed one to test the existing interpretation
s of the Mossbauer spectra of FeC austenite. It was shown that the con
centration dependence of the carbon activity at different temperatures
can be successfully described only by taking into account CC interact
ions in several coordination spheres: a weak repulsion in the first co
ordination sphere and a stronger one in the second sphere. This corres
ponds to the interpretation of Mossbauer spectra as consisting of the
component of ''pure'' iron atoms, Fe-0, iron atoms with one carbon ato
m as a nearest neighbour, Fe-1, and iron atoms with paired carbon atom
s in the neighbouring interstitial sites, Fe-2-90'. It is shown that s
uperstructures like Fe4C1-x and Fe8C1-x proposed in some Mossbauer stu
dies of FeC austenite could exist only at those combinations of C-C in
teraction parameters in the first, second and third coordination spher
es which are not consistent with the values of the carbon activity. Co
pyright (C) 1996 Acta Metallurgica Inc.