Production and segregation of transmutation elements Ca, Ti, Sc in the F82H steel under mixed spectrum irradiation of high energy protons and spallation neutrons

摘要

Ferritic/martensitic steel F82H was irradiated at 345℃ in a mixed proton–neutron spectrum in the Swiss spallation neutron source up to 20.3 dpa. Nanoscale investigations using the atom probe tomography(APT) technique were performed in order to study the atomic scale evolution of the microstructure of the F82H steel under irradiation. Spallation products Ca, Ti and Sc have been detected. The irradiation led to the production of about 370 appm of Ca, 90 appm of Sc and 800 appm of Ti. APT experiments revealed that regardless their low bulk concentrations, the spallation products extensively participate in the evolution of the microstructure: formation of radiation-induced clusters, segregation at the dislocation loops and alteration of the microchemistry of carbides. In this paper, a quantitative description of the observed features is presented and results are compared with TEM data of the literature obtained on the same steel and under similar irradiation conditions.