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Indexed by:Journal Papers

Date of Publication:2015-06-15

Journal:ACTA MATERIALIA

Included Journals:SCIE、EI、Scopus

Volume:92

Page Number:178-188

ISSN No.:1359-6454

Key Words:Conductive atomic force microscopy; Irradiation; Tungsten

Abstract:Polycrystalline tungsten (W) has been irradiated with a low-energy (30-830 eV) He+ beam at the W surface temperature of 523-1073 K up to a fluence of 1.0 x 10(25)/m(2). Measurements by non-destructive conductive atomic force microscopy show the existence of nanometer-sized interstitial loops in He+-implanted layer. The size and distribution of interstitial loops are significantly affected by He+ energy and fluence, and W surface temperature. The distribution of interstitial loops becomes orientated in one certain direction after being irradiated at a relatively high fluence or W surface temperature. The cascading slipping of W atoms along one certain dense-packed face has been proposed to explain the ordered arrangement of interstitial loops at elevated temperature. Analysis indicates that the continuous growth of unstable nanometer-sized interstitial loops can result in the surface exfoliation of W materials. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.