Effect of grain boundaries on fracture toughness in ultrafine-grained metals by atomic-scale computational experiments

Tomotsugu Shimokawa, Masaki Tanaka, Kenji Higashida

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    In order to investigate roles of grain boundaries on the improved fracture toughness in ultrafine-grained metals, interactions between crack tips, dislocations, and disclination dipoles at grain boundaries are performed to aluminium bicrystal models containing a crack and <112> tilt grain boundaries using molecular dynamics simulations. A proposed mechanism to express the improved fracture toughness in ultrafine-grained metals is the disclination shielding effect on the crack tip mechanical field. The disclination shielding can be activated when a transition of dislocation sources from crack tips to grain boundaries and a transition of the grain boundary structure into a neighbouring energetically stable boundary by emitting dislocations from the grain boundary occur. The disclination shielding effect becomes large as dislocations are continuously emitted from the grain boundary without dislocation emissions from crack tips. This mechanism can further shield the mechanical field around the crack tip and obtain the plastic deformation by dislocation emissions from grain boundaries, hence it can be expected that the disclination shielding effect can improve the fracture toughness in ultrafine-grained metals.

    Original languageEnglish
    Title of host publicationTHERMEC 2011
    PublisherTrans Tech Publications Ltd
    Pages1841-1846
    Number of pages6
    ISBN (Print)9783037853030
    DOIs
    Publication statusPublished - 2012
    Event7th International Conference on Processing and Manufacturing of Advanced Materials, THERMEC'2011 - Quebec City, QC, Canada
    Duration: Aug 1 2011Aug 5 2011

    Publication series

    NameMaterials Science Forum
    Volume706-709
    ISSN (Print)0255-5476
    ISSN (Electronic)1662-9752

    Other

    Other7th International Conference on Processing and Manufacturing of Advanced Materials, THERMEC'2011
    Country/TerritoryCanada
    CityQuebec City, QC
    Period8/1/118/5/11

    All Science Journal Classification (ASJC) codes

    • Materials Science(all)
    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering

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