Effect of carbon and nitrogen on chemical homogeneity of Fcc iron-based alloys

Iron-based fee alloys containing (at. pct) 18 Cr, 15Ni, 10Mn and 18Cr, 15Ni were additionally alloyed with either carbon or nitrogen and studied by the small angle scattering of thermal polarized neutrons. Carbon and nitrogen were found to influence neutron scattering in opposite ways. An increase in carbon content enhances the inhomogeneity of the solid solution on a scale that significantly exceeds the lattice parameter. Nitrogen, on the contrary, slightly decreases the inhomogeneity of FeCrNiMn and FeCrNi austenites. The data obtained are discussed in terms of short-range atomic order and enable one to clarify the physical reason for differences in the thermodynamical stability of multicomponent iron-based fee solid. solutions alloyed with either carbon or nitrogen, which is important for the development of high-strength corrosion-resistant alloys.