Interaction between the deformation and the irradiation defect clusters in austenitic steels

The response of the irradiation-induced microstructure to deformation was examined in a model alloy (Fe/18wt%Cr/14wt%Ni) irradiated at about 1 dpa with 700 keV Kr2+ ions at temperatures varying from 523 to 873 K. Different microstructures are observed: from a high density of black dots to large isolated loops. When the microstructure consists of large loops, after strain the main fraction of loops becomes unfaulted and the glide is localised in planes. We observe the agglomeration of perfect loops by glide and helical screw dislocations. Only a few examples of pinning have been scarcely detected. We analyse configurations of perfect loops which tend to come together. In a 20% cold-worked 316L stainless steel irradiated by Kr2+ ions at 623 K we observe the evolution of the dislocation cells from 1 to 5 dpa. No initial network remains at 5 dpa and small loops appear. (orig.)