On the helium bubble swelling in nano-oxide dispersion-strengthened steels. (10th April 2022)

• Record Type: Journal Article
• Authors: Krsjak, Vladimir; Shen, Tielong; Degmova, Jarmila; Sojak, Stanislav; Korpas, Erik; Noga, Pavol; Egger, Werner; Li, Bingsheng; Slugen, Vladimir; Garner, Frank A.
• Is Part Of: Journal of materials science & technology. Volume 105(2022)
• Page Start: 172
• Page End: 181
• Publication Date: 2022-04-10
• Subjects: Ion irradiation -- Bubble swelling -- Helium -- Positron annihilation spectroscopy -- Oxide dispersion strengthened steels; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2021.08.004
• Languages: English
• ISSNs: 1005-0302

Abstract

Highlights: Radiation-induced volumetric bubble swelling in ODS steels has been investigated using a novel experimental approach. Superior radiation resistance of the ODS steels dominates in the early stages of helium bubble evolution. The incubation period for helium bubble growth is directly linked to open-volume defects at oxide/matrix interfaces. Abstract: The development of structural materials resistant to harsh radiation environments requires an in-depth understanding of the early stage of the aging processes. In radiation environments with high transmutation helium production rates such as in fusion and spallation applications, even materials with otherwise acceptable radiation stability may suffer from radiation embrittlement related to helium bubble formation. While theoretical modeling of helium-assisted cavity nucleation in pure metals and simple alloys provides some useful guidelines at the atomic scale level, these, however, do not overlap with the size resolution of available experimental techniques. In this study, we employed slow positron beam spectroscopy to characterize the nucleation and growth of nano-scale helium bubbles in martensitic steels strengthened by thermodynamically stable nano-oxide dispersoids. In combination with transmission electron microscopy, we experimentally characterized the evolution of helium bubbles from small clusters of radiation-induced vacancies to large cavities well resolvable by TEM. Superior radiation resistance of oxide-dispersion strengthened steels dominates only in the early stages of bubble evolution, where positron lifetime measurements provide a missing piece of the microstructural puzzle conventionally constructed by TEM. Graphical abstract: Image, graphical abstract