Radiation-induced grain boundary segregation in austenitic stainless steels

Radiation-induced segregation to grain boundaries in austenitic stainless steels has been evaluated for a wide range of solute species, temperatures, irradiation dose and dose rate, and irradiation particle type. The primary findings from measurement and modeling are that major alloying elements (Fe, Ni and Cr) segregate predominately by the inverse-Kirkendall mechanism and undersized minor elements segregate by the interstitial-association mechanism. Several hundred measurements of radiation-induced grain boundary composition have been analyzed and rate theory models of solute-point defect interactions are shown to be useful descriptors of the segregation process. This fundamental study of segregation has aided the definition of grain boundary microchemistry during exposure to neutron irradiation in power reactors and relates to the specific problem of irradiation-assisted stress corrosion cracking.