A method was proposed for quantifying inverse-Kirkendall segregation during the irradiation of a stainless steel which contained about 21at%Cr and 20at%Ni. Model predictions of the Cr depletion, when compared with the calculated Ni enrichment, were found to be in accord with several hundred compositional measurements. The compositions were measured at, and near to, grain boundaries in a Ni ion-irradiated stainless steel. The method permitted the assessment of relative defect-solute coupling efficiencies, regardless of the kinetics of segregation. Analysis of the relative composition changes established that the Fe diffusivity was 2.0 times faster than the Ni diffusivity, and that the Cr diffusivity was 2.55 times faster than the Ni diffusivity at temperatures ranging from 230 to 550C. These relative rates were consistent with the reported rates for non-irradiated ternary diffusion rates at higher temperatures.

E.P.Simonen, L.A.Charlot, S.M.Bruemmer: Journal of Nuclear Materials, 1995, 225, 117-22