Effect of irradiation temperature on microstructure of ferritic-martensitic ODS steel

The EUROFER-ODS alloy with 0.5% Y2O3 was neutron irradiated with doses up to 16.2 dpa at 250 degrees C, 350 degrees C and 450 degrees C. The radiation induced changes in the microstructure (e.g. dislocation loops and voids) were investigated using transmission electron microscopy (TEM). The number density of radiation induced defects was found to be significantly lower than in EUROFER 97 irradiated at the same conditions. It was found that the appearance and extent of radiation damage strongly depend not only on the irradiation temperature but also on the local number density and size distribution of ODS particles. The higher number density of dislocation loops and voids was found in the local areas with low number density of ODS particles. The interstitial loops with Burgers vector of both 1/2 < 111 > and < 100 > types were detected by imaging using different diffraction conditions. (C) 2017 Published by Elsevier B.V.