Journal of Solid Mechanics and Materials Engineering
Online ISSN : 1880-9871
ISSN-L : 1880-9871
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Transfer and Incorporation of Dislocations to Σ3 Tilt Grain Boundaries under Uniaxial Compression
Yoji SHIBUTANITomoyuki HIROUCHITomohito TSURU
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2013 Volume 7 Issue 6 Pages 571-584

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Abstract

Microscopic yielding can be realized by the transfer of a dislocation across a grain boundary (GB), or by incorporation between the residual GB dislocation and the dislocations nucleated in the near-field of a GB due to the applied stress. These phenomena are determined by the crystallographic orientation and the multiaxial stress state around a GB. In the present paper, a new boundary interaction criterion of L- or L'-value is proposed, which considers both the contributions of the geometric relationship between two grains and a GB, and the stress state applied to the near-field of a GB. This value and the others so far proposed were calculated for <110>, <100>, and <111> symmetric tilt grain boundaries under uniaxial compression normal to the GB. The dynamic transfer and incorporation of the dislocations nucleated under uniaxial compression normal to the GB plane were then examined using 3-dimensional molecular dynamics simulations. Two kinds of <110> symmetric tilt boundaries of copper Σ3A and Σ3B were atomistically modeled. The individual reaction process between the dislocations nucleated from an artificial Frank-Read source introduced in one grain and a GB under uniaxial compression was resolved in detail. Combinations of the preferential slip systems across GBs were discussed in reference to the proposed boundary interaction criterion. The case of Σ3B with an easier slip transfer across a GB is identical to that predicted, while incorporation of the displacement shift complete (DSC) dislocation migrated on a Σ3A boundary plane complicates the defect reaction, necessitating a larger critical stress for slip transfer across a GB.

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© 2013 by The Japan Society of Mechanical Engineers
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