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

Abstract

This work examines the variability in grain boundary segregation measurements in proton irradiated iron–chromium–nickel alloys made using Auger electron spectroscopy (AES) and scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM-EDS). Variability occurs in segregation measurements made on different boundaries in the same sample and made on different samples irradiated under the same conditions. Variability occurs in each measurement technique, but is greater for AES. A portion of the greater variability in the AES measurements occurs because only the concentrations calculated from AES measurements are sensitive to changes in the shape of the energy intensity peak. A statistical analysis technique for testing the consistency of experimental conditions demonstrated that the variability 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 environmental cracking by controlling grain boundary composition need to focus on both the average grain boundary compositions and the shape of the concentration distributions.