Variability of radiation-induced segregation in iron-chromium-nickel alloys

This work examines the variability in grain boundary segregation measuremen ts in proton irradiated iron-chromium-nickel alloys made using Anger electr on spectroscopy (AES) and scanning transmission electron microscopy with en ergy dispersive X-ray spectroscopy (STEM-EDS). Variability occurs in segreg ation measurements made on different boundaries in the same sample and made on different samples irradiated under the same conditions. Variability occ urs in each measurement technique, but is greater for AES. A portion of the greater variability in the AES measurements occurs because only the concen trations calculated from AES measurements are sensitive to changes in the s hape of the energy intensity peak. A statistical analysis technique for tes ting the consistency of experimental conditions demonstrated that the varia bility is not attributable to uncertainty in irradiation temperature, dose, or material condition. Finally, the analysis of grain boundary composition distributions in Fe-20Cr-9Ni indicates that attempts to minimize environme ntal cracking by controlling grain boundary composition need to focus on bo th the average grain boundary compositions and the shape of the concentrati on distributions. (C) 2000 Elsevier Science B.V. All rights reserved.