Dislocation Generation from Grain Boundaries in Nanosized Cu-beams

Forskningsoutput: KonferensbidragKonferensabstract

Abstract

As the dimensions of a structure are decreased towards the nanometer scale, the mechanical response to loading deviates from what is observed macroscopically. This is due to a change in material properties stemming from the relative increase in number of surface atoms as compared to bulk atoms. Surface atoms lack some of their neighboring atoms, leading to a reorganization of the electron clouds and, thereby, to energy states differing from those of bulk atoms. Also at a grain boundary the atomic lattice is disturbed, and bonds between atoms in regions of different lattice orientations must be formed. The energy states of atoms close to such a disorder differ from the states for bulk atoms. All disturbed atomic regions are prone to dislocation interactions under mechanical loading. This should be especially true in the vicinity of both a surface and a grain boundary. Here we investigate tensile loading of nanosized Cu-beams, of length 100a0, with a0 denoting the lattice parameter, and with square cross sections with side length between 6a0 and 48a0 by molecular dynamic simulation. A grain boundary, normal to the loading direction, is introduced at the center of the beam to create two grains. The grain boundaries investigated are between the lattice orientations [100], [110] and [111], i.e. in all three combinations. Under loading dislocations are generated from the grain boundaries and extend into the weakest of the two grains. No dislocations pass a grain boundary or extend into both grains. It is also found that the yield stress decreases in the presence of a grain boundary as compared to a single grain beam. The stress-stain curves themselves are ragged and a correlation between the development of the dislocation density and the raggedness is observed.

Detaljer

Författare
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Teknisk mekanik

Nyckelord

  • Grain boundary, Dislocation generation, Nanosized Cu-beams, Molecular dynamic simulations
Originalspråksvenska
Antal sidor2
StatusPublished - 2019 aug 5
PublikationskategoriForskning
Peer review utfördJa
EvenemangThe fourth International Symposium on Atomistic and Multiscale Modeling of Mechanics and Multiphysics - Friedrich-Alexander Universität , Erlangen-Nürnberg (FAU), Tyskland
Varaktighet: 2019 aug 52019 aug 7
Konferensnummer: 4
http://www.cmsm.iis.u-tokyo.ac.jp/isam4/

Konferens

KonferensThe fourth International Symposium on Atomistic and Multiscale Modeling of Mechanics and Multiphysics
Förkortad titelISAM4-2019
LandTyskland
OrtErlangen-Nürnberg (FAU)
Period2019/08/052019/08/07
Internetadress

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