Mn-C interaction in Fe-C-Mn steels: Study by thermoelectric power and internal friction

A new methodology based on the coupling of thermoelectric power (TEP) and internal-friction (IF) measurements was developed to evaluate quantitatively the two populations of carbon atoms present in the solid solution of Fe-C-Mn steels: one is constituted of single carbon atoms and the other of carbon atoms in interaction with manganese atoms. From the evaluation of the concentration of these two populations at different temperatures and assuming that the distribution of the carbon atoms in the iron matrix can be described by the Maxwell-Boltzmann statistical theory, the binding energy of the Mn-C dipoles could be assessed. Finally, this methodology was used to follow the precipitation kinetics of the two populations of carbon atoms during an isothermal treatment.