Speaker
Description
Oxide dispersion strengthened steels are potential structural materials for the next generation of fast neutron reactors. It is assumed that they will be able to withstand radiation exposure up to doses of around 200 dpa (displacements per atom) at operating temperatures of 400-700 ° C.
Production method of powder metallurgy allows for size and composition optimization of small inclusions, which leads to an increase of mechanical properties and radiation stability of affected steels.
To analyze the distribution of oxide inclusions in ODS steels, usually a combination of a transmission electron microscopy and atom probe tomography is used. Atom probe provides high detection accuracy of nanofeatures chemical composition with spatial distribution of atom species.
In addition to the study of the initial state of the steel sample, similar studies were conducted for the irradiated samples to observe stability of inclusions and of the entire microstructure. Irradiated samples were obtained through ion beam irradiation, since it is considered that the types of defects (as well as their size and number density) caused by neutron bombardment from the nuclear reaction to be closely reproduced with the ion beam experiments.
This paper presents the results of an atom probe study of 10Cr ODS steel, which is produced in Korea Atomic Energy Research Institute. Specimens were irradiated at 350° C to several doses up to 30 dpa. For all investigated sample volumes, average values of concentrations were determined and the spatial characteristics of the detected inclusions were evaluated. Overall with the increase in irradiation dose, the cluster enrichment in yttrium and oxygen decreased whereas enrichment in vanadium and titanium increased instead.
| Speaker Country | Russia |
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