Analysis of Defect Microstructures in Irradiated Ferritic Alloys

Abstract

The defect microstructures in a series of neutron-irradiated Fe-Cu binary alloys (0-0.86 at% Cu) and reactor pressure vessel steels (> 0.1 wt% Cu) have been investigated using magnetic and nuclear small angle neutron scattering (SANS) and transmission electron microscopy (TEM). Specimens were irradiated in the FRG-2 reactor in Geesthacht to fluences > 10 23 n/m 2 at 290 °C. Under these conditions, the defect microstructures in the irradiated binary alloys could be analyzed using both SANS and TEM, and consist of distributions of Cu precipitates, voids, and interstitial loops; in the steels, for which only SANS could be applied, the scattering data and the post-irradiation annealing behaviour appear to be consistent with a defect microstructure consisting of Cu-rich precipitates and voids, at least in steels containing> 0.1 wt% Cu.