Thesis
Atomistic simulation of the mechanical behavior of asymmetric tilt grain boundaries in AL and CU bicrystals
Washington State University
Master of Science (MS), Washington State University
2018
Handle:
https://hdl.handle.net/2376/102007
Abstract
Grain boundaries (GBs) are important microstructure attributes and can impact the properties of nanocrystalline materials. With decreasing the grain size less than 100 nm, the dislocation activities become dominant at the GBs in compare to the interior grains. GBs can act as an obstacle for dislocation propagation and as a new source for dislocations, therefore, they are responsible for the majority of plastic deformations. Atomistic simulation such as molecular dynamic (MD) simulation can be used to model the nucleation of dislocations from different grain boundaries. The objective of this paper is to investigate dislocation nucleation mechanisms from different ATGBs using molecular dynamics simulation for Al and Cu bicrystals that represent both high and low stacking fault energy materials. Bicrystals of [sigma]5, [sigma]9, [sigma]11, and [sigma]13 are built considering different inclination angles and are deformed under uniaxial tension perpendicular to the GB plane at a constant rate. GB structural evolution including coarsening and emission of intrinsic stacking fault facets, nucleation of partial dislocation on primary and secondary slip planes, and full dislocation nucleation loops are of predominant features which are observed. Grain boundaries energy and the stress required for dislocation nucleation are also calculated which are found in agreement with similar experimental and simulation works.
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Details
- Title
- Atomistic simulation of the mechanical behavior of asymmetric tilt grain boundaries in AL and CU bicrystals
- Creators
- Farzaneh Sharifi
- Contributors
- Sinisa Dj Mesarovic (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525073201842
- Language
- English
- Resource Type
- Thesis