RADIATION-INDUCED SEGREGATION ACCOMPANIED BY GRAIN-BOUNDARY MIGRATIONIN AUSTENITIC STAINLESS-STEEL

A computer simulation and an electron irradiation in a high voltage el ectron microscope (1000 kV) were used to study radiation-induced solut e segregation and point defect flow in typical austenitic Fe-Cr-Ni all oys. The calculation was conducted by solving the coupled rate equatio ns for solute and defect concentrations considering the Kirkendall eff ect at a moving grain boundary sink. The experimental solute redistrib ution profiles were explained qualitatively. Redistribution of nickel and chromium solutes near the grain boundaries and simultaneously grai n boundary migration occurred during irradiation. The amount of nickel enrichment at a grain boundary was especially remarkable, comparing t o the amount of chromium depletion. It is suggested that grain boundar y migration may contribute to the flow of under-sized nickel solute to ward the boundary. The influence of the probe size on EDS analysis of compositional profiles was investigated, with some experimental data.