Hollow-cone dark-field transmission electron microscopy for dislocation density characterization of trimodal Al composites

    Authors

    B. Yao; H. Heinrich; C. Smith; M. van den Bergh; K. Cho;Y. H. Sohn

    Comments

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    Abbreviated Journal Title

    Micron

    Keywords

    Transmission electron microscopy; Dislocation density; Nanocrystalline; Hollow-cone dark-field; Two beam condition; STRENGTH; DUCTILITY; MATRIX; METAL; Microscopy

    Abstract

    This paper describes a methodology based on hollow-cone dark-field (HCDF) transmission electron microscopy (TEM) to study dislocation structures in both nano- and micro-crystalline grains Although the conventional approach based on a two-beam condition has been commonly used to acquire weak-beam dark-field (WBDF) TEM images for dislocation structure characterization it is very challenging to employ this technique to study nanocrystalltne materials especially when the grams are less than 100 nm in diameter Compared to the conventional two-beam approach the method described in this paper is more conducive for obtaining high-quality WBDF-TEM images Furthermore the method is suitable for studying samples with both nanocrystalline and coarse-grains A trimodal Al metal-matrix-composite (MMC) consisting of B(4)C particles a nanocrystalline Al (NC-Al) phase and a coarse-grained Al (CG-Al) phase has been reported to exhibit an extremely high strength and tailorable ductility The dislocations in both NC-Al and CG-Al phases of the trimodal Al MMCs at different fabrication stages were examined using the HCDF method described The influence of the dislocation density in both NC-Al and CG-Al phases on the strength and ductility of the composite is also discussed (C) 2010 Elsevier Ltd All rights reserved

    Journal Title

    Micron

    Volume

    42

    Issue/Number

    1

    Publication Date

    1-1-2011

    Document Type

    Review

    Language

    English

    First Page

    29

    Last Page

    35

    WOS Identifier

    WOS:000284677300005

    ISSN

    0968-4328

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