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 transmuta-tion 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 forma-tion.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 spec-troscopy 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 clus-ters 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 con-structed by TEM.

Vladimir Krsjak;Tielong Shen;Jarmila Degmova;Stanislav Sojak;Erik Korpas;Pavol Noga;Werner Egger;Bingsheng Li;Vladimir Slugen;Frank A.Garner

Slovak University of Technology,Faculty of Electrical Engineering and Information Technology,Institute of Nuclear and Physical Engineering,Ilkovicova 3,Bratislava 81219,Slovakia;Slovak University of Technology,Faculty of Materials Science and Technology,Advanced Technologies Research Institute,Jana Bottu 2781/25,Trnava 91724,Slovakia;Chinese Academy of Sciences,Institute of Modern Physics,Lanzhou 730000,China;Universit?t der Bundeswehr München,Institut für Angewandte Physik und Messtechnik LRT2,Werner-Heisenberg-Weg 39,Neubiberg,85577,Germany;Southwest University of Science and Technology,State Key Laboratory for Environment-friendly Energy Materials,Mianyang,Sichuan 621010,China;Texas A&M University.Nuclear Engineering Department,College Station,TX 77843,USA;Radiation Effects Consulting LLC,Richland WA 99354,USA

材料科学技术（英文版）

[1]Vladimir Krsjak;Tielong Shen;Jarmila Degmova;Stanislav Sojak;Erik Korpas;Pavol Noga;Werner Egger;Bingsheng Li;Vladimir Slugen;Frank A.Garner-.On the helium bubble swelling in nano-oxide dispersion-strengthened steels)[J].材料科学技术（英文版）,2022(10):172-181

transmuta,dispersoids

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