Shear stress- and line length-dependent screw dislocation cross-slip in FCC Ni

dc.contributor.author Xiong, Liming
dc.contributor.author Xiong, Liming
dc.contributor.author Chen, Youping
dc.contributor.author McDowell, David L.
dc.contributor.department Aerospace Engineering
dc.date.accessioned 2022-02-17T22:45:08Z
dc.date.available 2022-02-17T22:45:08Z
dc.date.issued 2017-01-01
dc.description.abstract Screw dislocation cross-slip is important in dynamic recovery of deformed metals. A mobile screw dislocation segment can cross slip to annihilate an immobile screw dislocation segment with opposite Burgers vector, leaving excess dislocations of one kind in a crystal. Previous studies have found that the cross-slip process depends on both the local stress state and dislocation line length, yet a quantitative study of the combined effects of these two factors has not been conducted. In this work, we employ both dynamic concurrent atomistic-continuum (CAC) [L. Xiong, G. Tucker, D.L. McDowell, Y. Chen, J. Mech. Phys. Solids 59 (2011) 160–177] and molecular dynamics simulations to explore the shear stress- and line length-dependent screw dislocation cross-slip in face-centered cubic Ni. It is demonstrated that the CAC approach can accurately describe the 3-D cross-slip process at a significantly reduced computational cost, as a complement to other numerical methods. In particular, we show that the Fleischer (FL) [R.L. Fleischer, Acta Metall. 7 (1959) 134–135] type cross-slip, in which a stair-rod dislocation is involved, can be simulated in the coarse-grained domain. Our simulations show that as the applied shear stress increases, the cross-slip mechanism changes from the Friedel-Escaig (FE) [B. Escaig, J. Phys. 29 (1968) 225–239] type to the FL type. In addition, the critical shear stress for both cross-slip mechanisms depends on the dislocation line length. Moreover, the cross-slip of a screw dislocation with a length of 6.47 nm analyzed using periodic boundary conditions occurs via only the FL mechanism, whereas a longer dislocation with length of 12.94 nm can cross-slip via either the FE or FL process in Ni subject to different shear stresses.
dc.description.comments This is a manuscript of an article published as Xu, Shuozhi, Liming Xiong, Youping Chen, and David L. McDowell. "Shear stress-and line length-dependent screw dislocation cross-slip in FCC Ni." Acta Materialia 122 (2017): 412-419. DOI: 10.1016/j.actamat.2016.10.005. Copyright 2016 Acta Materialia Inc. Posted with permission.
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/Rwyq91Bw
dc.language.iso en_US
dc.publisher Elsevier Ltd.
dc.source.uri https://doi.org/10.1016/j.actamat.2016.10.005 *
dc.subject DegreeDisciplines::Engineering::Aerospace Engineering::Structures and Materials
dc.title Shear stress- and line length-dependent screw dislocation cross-slip in FCC Ni
dc.type Article
dspace.entity.type Publication
relation.isAuthorOfPublication 19ad205a-f06f-45c3-a6bf-79d9d1d97a68
relation.isOrgUnitOfPublication 047b23ca-7bd7-4194-b084-c4181d33d95d
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