Carbon solubilities in iron at elevated temperatures analysed by statistical thermodynamics

Abstract

Carbon solubilities in iron at elevated temperatures (>1000 K) are analysed on the basis of statistical thermodynamics. A parameter Q which refers to the extent of stabilization of a carbon atom in the iron lattice is estimated for α-, γ-, and molten FeCx phases. The results suggest that the carbon atom is most stable in molten FeCx and least stable in (α-FeCx. In addition, the value of QCα for (α-FeCx at high temperatures appears to be different from that at lower temperatures. This observation can be interpreted as the effect of the magnetic transition of the iron atom around the Curie temperature. The values for Q estimated for the other interstitial elements X (X = H, N, P, S) in iron lattices are compared.MST/586