Indexed by:Journal Papers

Date of Publication:2019-12-15

Journal:JOURNAL OF NUCLEAR MATERIALS

Included Journals:SCIE

Volume:527

ISSN No.:0022-3115

Abstract:In this study, polycrystalline W, W-Re alloys, and La2O3 and Y2O3 dispersion-strengthened W have been irradiated by our large-power materials irradiation experimental system (LP-MIES) at the irradiation temperature of 1360-1460 K. Our measurements show that the W nano-fuzz layer which is <5.2 mu m thick has been formed over all the specimens exposed to the low-energy (50 or 100 eV) and high-flux (1.37 x 10(22 )-1.62 x 10(22) ions/m(2).s) He+ irradiations. The mass loss of the fuzz layer almost linearly increases with the He+ fluence, which does not show any dependence on the thickness of fuzz layer varying from 1.1 to 5.2 mu m La2O3 and Y2O3 dispersions into W significantly suppress the growth of W fuzz, indicating that He diffusion and the evolution of He nano-bubbles in the near-surface can be significantly influenced due to the dispersion. After He+ (100 eV) irradiation at He+ fluence of 5.83 x 10(26)/m(2), the mass loss of 0.1 vol% - 1.0 vol% La2O3 -dispersed W is about 20% lower than the one of the pure W, and the La2O3 dispersed W exhibits the best erosion resistance among various W material grades. Our analysis indicates that both the surface sputtering of W fuzz by energetic ions and surface bursting of He nano-bubbles can be responsible for the mass loss of W under ITER-relevant He+ irradiations. (C) 2019 Elsevier B.V. All rights reserved.