Investigation of interstitial carbon in the disordered bcc FeCr alloys

The solution enthalpy of interstitial carbon in the ferromagnetic bcc Fe-Cr disordered alloys was calculated. It was found that the enthalpy depends on the number of chromium atoms in the octahedron constituting the octahedral pore and their positions, as well as on the magnetic states of the lattice atoms (Fe/Cr) surrounding the interstitial atom. The lowest cell energy corresponds to the configuration in which only chromium atoms are in the first coordination sphere of the carbon atom. The magnetic moments of the carbon and the nearest lattice atoms show dependency from their distances. For the most energetically favorable configurations, the values of the enthalpy of carbon dissolution in Fe-Cr alloy and in α-Fe are close to each other. It is found that these configurations correspond to the states in which the local magnetic moment on the interstitial carbon atom is close to zero. Also the elastic constants of the Fe-Cr-C alloy were calculated, and it is shown that alloying with carbon slightly increases the elastic properties of Fe-Cr alloys. [Display omitted] •Calculation of carbon solution enthalpy in ferromagnetic bcc disordered FeCr alloys.•Analysis of the magnetic states of C, Fe and Cr surrounding the interstitial atom.•Chemical and magnetic environment of interstitial impurity affects carbon solution enthalpy.•Configuration with only Cr in the 1st coordination sphere of C atom have lowest energy.