Dislocation dynamics in polycrystals with atomistic-informed mechanisms of dislocation - grain boundary interactions

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dc.contributor.author Burbery, NB en
dc.contributor.author Po, G en
dc.contributor.author Das, R en
dc.contributor.author Ghoniem, N en
dc.contributor.author Ferguson, WG en
dc.date.accessioned 2017-06-30T00:09:50Z en
dc.date.issued 2017-03 en
dc.identifier.citation Journal of Micromechanics and Molecular Physics 02(01):1750003 Mar 2017 en
dc.identifier.issn 2424-9130 en
dc.identifier.uri http://hdl.handle.net/2292/33889 en
dc.description.abstract In polycrystalline materials, dislocations can interact with grain boundaries (GBS) through a number of mechanisms including dislocation absorption, pile-up formation, dissociation reactions within the GB plane and (possibly) dislocation nucleation from the interface itself. The effects of dislocation pile-ups contribute significantly to the mechanical behavior of polycrystalline materials by creating back-stresses that inactivate the primary slip systems in the vicinity of the interface, corresponding with the celebrated Hall–Petch relationship between size and strength. However, dislocation pile-ups cannot be contained within the small grain sizes that can be accommodated by molecular dynamics simulations, which to-date remain the primary computational method used to study the discrete structure of GBs. Dislocation dynamics (DD) simulations are a promising framework for computational modeling that are used to provide insights about phenomena that can only be explained from the intermediate scale between atomistic and macro scales. However, a robust framework for modeling dislocation interactions with internal microstructure such as grain boundaries (GBs) has yet to be achieved for 3D models of DD. Furthermore, this is the first implementation which explicitly includes the dislocation content of the interface. The framework described in this paper is effective for studying GB-dislocation interactions (including inter-granular effects) and the approach for partitioning the DD simulation domain. To achieve a robust method to differentiate between crystal regions, the present framework utilizes a mesh-based partitioning system. Within each grain, slip systems are determined by the grain orientation. The versatile construction described, allows modeling of an arbitrary crystallography, size and grain geometry. Extrinsic dislocations that intersect the interface are constrained to glide on the line of intersection between the glide plane and GB plane. Atomistically informed criteria for slip transmission are implemented, based on the geometrically optimal outgoing glide plane which shares a common line of intersection on the GB plane. Slip transmission is only initiated when the resolved shear stress in one of the compatible outgoing slip directions exceeds an approximate threshold resolved shear stress, which is based on observations made with molecular dynamics studies. The primary aim of the present study was to establish a sufficiently ‘generic’ framework to enable the modelling of various GB structures, polycrystal geometries and crystallographic orientations. The framework described in the present work provides a means to study multi-grain deformation processes governed by dislocations pile-ups at GBs, in detail beyond feasible limits of experiments or atomistic simulation approaches. en
dc.publisher World Scientific Publishing en
dc.relation.ispartofseries Journal of Micromechanics and Molecular Physics en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.title Dislocation dynamics in polycrystals with atomistic-informed mechanisms of dislocation - grain boundary interactions en
dc.type Journal Article en
dc.identifier.doi 10.1142/S2424913017500035 en
pubs.issue 01 en
pubs.volume 02 en
dc.rights.holder Copyright: World Scientific Publishing en
pubs.publication-status Published en
dc.rights.accessrights http://purl.org/eprint/accessRights/RestrictedAccess en
pubs.subtype Article en
pubs.elements-id 620625 en
dc.identifier.eissn 2424-9149 en
pubs.number 1750003 en
pubs.record-created-at-source-date 2017-06-30 en

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