Nanoindentation and TEM to Study the Cavity Fate after Post-Irradiation Annealing of He Implanted EUROFER97 and EU-ODS EUROFER

Abstract

first_pagesettingsOrder Article Reprints Open AccessArticle Nanoindentation and TEM to Study the Cavity Fate after Post-Irradiation Annealing of He Implanted EUROFER97 and EU-ODS EUROFER by Marcelo Roldán 1,2,*ORCID,Pilar Fernández 1,Joaquín Rams 2,Fernando José Sánchez 1 andAdrián Gómez-Herrero 3 1 Division of Fusion Technologies, National Fusion Laboratory, CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain 2 Department of Applied Mathematics, Materials Science and Engineering and Electronic Technology, School of Experimental Sciences and Technology, Rey Juan Carlos University, C/Tulipán s/n, 28933 Móstoles, Spain 3 Centro Nacional de Microscopía Electrónica, Universidad Complutense de Madrid, 28040 Madrid, Spain * Author to whom correspondence should be addressed. Micromachines 2018, 9(12), 633; https://doi.org/10.3390/mi9120633 Submission received: 25 October 2018 / Revised: 22 November 2018 / Accepted: 23 November 2018 / Published: 29 November 2018 (This article belongs to the Special Issue Small Scale Deformation using Advanced Nanoindentation Techniques) Downloadkeyboard_arrow_down Browse Figures Review Reports Versions Notes

Abstract The effect of post-helium irradiation annealing on bubbles and nanoindentation hardness of two reduced activation ferritic martensitic steels for nuclear fusion applications (EUROFER97 and EU-ODS EUROFER) has been studied. Helium-irradiated EUROFER97 and EU-ODS EUROFER were annealed at 450 °C for 100 h in an argon atmosphere. The samples were tested by nanoindentation and studied by transmission electron microscopy extracting some focused ion beam lamellae containing the whole implanted zone (¿50 µm). A substantial increment in nanoindentation hardness was measured in the area with higher helium content, which was larger in the case of EUROFER97 than in EU-ODS EUROFER. In terms of microstructure defects, while EU-ODS EUROFER showed larger helium bubbles, EUROFER97 experienced the formation of a great population density of them, which means that the mechanism that condition the evolution of cavities for these two materials are different and completely dependent on the microstructure. Keywords: nanoindentation; reduced activation ferritic martensitic (RAFM) steels; helium irradiation; irradiation hardening; nuclear fusion structural materials