In-situ transmission electron microscopy observation of the evolution of dislocation loops and gas bubbles in tungsten during H2+ and He+ dual-beam irradiation

Dislocation loop and gas bubble evolution in tungsten were in-situ investigated under 30 keV H2+ and He+ dual-beam irradiation at 973 K and 1173 K. The average size and number density of dislocation loops and gas bubbles were obtained as a function of irradiation dose. The quantitative calculation and analysis of the migration distance of 1/2 ⟨111⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{111}\rangle$$\end{document} loops at low irradiation dose indicated that the main mechanism of the formation of ⟨100⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{100}\rangle$$\end{document} loops should be attributed to the high-density helium cluster inducement mechanism, instead of the 1/2 ⟨111⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{111}\rangle$$\end{document} loop reaction mechanism. H2+ and He+ dual-beam irradiation induced the formation of ⟨100⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{100}\rangle$$\end{document} loops and 1/2 ⟨111⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{111}\rangle$$\end{document} loops, while increasing the irradiation temperature would increase ⟨100⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{100}\rangle$$\end{document} loop percentage. The percentage of ⟨100⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{100}\rangle$$\end{document} loops was approximately 18.6% at 973 K and increased to 22.9% at 1173 K. The loop reaction between two 1/2 ⟨111⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{111}\rangle$$\end{document} loops to form a large-sized 1/2 ⟨111⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{111}\rangle$$\end{document} loop was in-situ observed, which induced not only the decrease of the number of 1/2 ⟨111⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{111}\rangle$$\end{document} loops but also the significant increase of their sizes. The ⟨100⟩\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\langle{100}\rangle$$\end{document} loops impeded the movement of dislocation line and tended to escape from it instead of being absorbed. With the increase of irradiation dose, the yield strength increment (Δσloop\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Delta {\sigma }_{\mathrm{l}\mathrm{o}\mathrm{o}\mathrm{p}}$$\end{document}) caused by the change of loop size and density increased first and then decreased slightly, while the yield strength increment (Δσbubble\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Delta {\sigma }_{\mathrm{b}\mathrm{u}\mathrm{b}\mathrm{b}\mathrm{l}\mathrm{e}}$$\end{document}) caused by the change of bubble size and density always increased. Meanwhile, within the current irradiation dose range, Δσloop\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Delta {\sigma }_{\mathrm{l}\mathrm{o}\mathrm{o}\mathrm{p}}$$\end{document} was much larger than Δσbubble\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\Delta {\sigma }_{\mathrm{b}\mathrm{u}\mathrm{b}\mathrm{b}\mathrm{l}\mathrm{e}}$$\end{document}.