Dislocation Generation from Grain Boundaries in Nanosized Cu-beams
(2019) The fourth International Symposium on Atomistic and Multiscale Modeling of Mechanics and Multiphysics- 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... (More)
- 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. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/ebd0f601-69f5-4815-b936-15a681acea46
- author
- Ahadi, Aylin LU ; Hansson, Per LU and Melin, Solveig LU
- organization
- publishing date
- 2019-08-05
- type
- Contribution to conference
- publication status
- published
- subject
- keywords
- Grain boundary, Dislocation generation, Nanosized Cu-beams, Molecular dynamic simulations
- pages
- 2 pages
- conference name
- The fourth International Symposium on Atomistic and Multiscale Modeling of Mechanics and Multiphysics
- conference location
- Erlangen-Nürnberg (FAU), Germany
- conference dates
- 2019-08-05 - 2019-08-07
- project
- Modelling mechanical properties at nanoscale by molecular dynamics
- language
- Swedish
- LU publication?
- yes
- id
- ebd0f601-69f5-4815-b936-15a681acea46
- date added to LUP
- 2019-03-15 12:39:01
- date last changed
- 2021-03-22 16:13:29
@misc{ebd0f601-69f5-4815-b936-15a681acea46,
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.}},
author = {{Ahadi, Aylin and Hansson, Per and Melin, Solveig}},
keywords = {{Grain boundary; Dislocation generation; Nanosized Cu-beams; Molecular dynamic simulations}},
language = {{swe}},
month = {{08}},
title = {{Dislocation Generation from Grain Boundaries in Nanosized Cu-beams}},
year = {{2019}},
}