A theoretical investigation was made, of the composition of grain-boundary regions, by means of the scanning transmission electron microscopy of irradiated austenitic alloys. The calculations were aimed at accounting for recent experimental situations in which Cr enrichment at the boundary coexisted with depletion in the adjacent matrix. The effects of probe size and electron scattering within the foil were convoluted with theoretical concentration distributions of radiation-induced segregation, and predictions were made as to the visibility of segregation to the grain boundary. Two important predictions were that, depending upon the experimental variables, up to 0.4 of a monolayer of Cr segregation could be present at the boundary; but might not be explicitly revealed. Also, the visibility of segregation in the presence of depletion was not optimized in the thinnest specimens.

J.M.Titchmarsh, S.Dumbill: Journal of Nuclear Materials, 1996, 227[3], 203-19