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    郑勇刚

    • 教授     博士生导师   硕士生导师
    • 主要任职:力学与航空航天学院副院长
    • 其他任职:工程力学系副主任(分管本科生、研究生培养)
    • 性别:男
    • 毕业院校:大连理工大学
    • 学位:博士
    • 所在单位:力学与航空航天学院
    • 学科:工程力学. 计算力学. 生物与纳米力学
    • 办公地点:一号综合实验楼626房间
    • 电子邮箱:zhengyg@dlut.edu.cn

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    Twin Boundaries merely as Intrinsically Kinematic Barriers for Screw Dislocation Motion in FCC Metals

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    论文类型:期刊论文

    第一作者:Zhang, Jiayong

    通讯作者:Zheng, YG (reprint author), Dalian Univ Technol, Fac Vehicle Engn & Mech, Dept Engn Mech, State Key Lab Struct Anal Ind Equipment, Dalian 116024, Peoples R China.

    合写作者:Zhang, Hongwu,Ye, Hongfei,Zheng, Yonggang

    发表时间:2016-03-10

    发表刊物:SCIENTIFIC REPORTS

    收录刊物:SCIE、PubMed

    卷号:6

    页面范围:22893

    ISSN号:2045-2322

    摘要:Metals with nanoscale twins have shown ultrahigh strength and excellent ductility, attributed to the role of twin boundaries (TBs) as strong barriers for the motion of lattice dislocations. Though observed in both experiments and simulations, the barrier effect of TBs is rarely studied quantitatively. Here, with atomistic simulations and continuum based anisotropic bicrystal models, we find that the long-range interaction force between coherent TBs and screw dislocations is negligible. Further simulations of the pileup behavior of screw dislocations in front of TBs suggest that screw dislocations can be blocked kinematically by TBs due to the change of slip plane, leading to the pileup of subsequent dislocations with the elastic repulsion actually from the pinned dislocation in front of the TB. Our results well explain the experimental observations that the variation of yield strength with twin thickness for ultrafine-grained copper follows the Hall-Petch relationship.