Molecular Dynamics Study of the Evolution of Rotational Atomic Displacements in a Crystal Subjected to Shear Deformation
The paper analyzes the redistribution of atomic displacements in an initially defect-free copper crystallite after shear deformation with emphasis on the evolution of dynamic structures formed by self-consistent collective atomic rotations. The analysis is based on an original technique which allows one to identify vortex motion in a vector variable space with a discrete step. The results of research show that the direction of consistent atomic motion in vortex structures varies with time and from vortex to vortex. Such spatial alternation of rotations in the material provides its continuity along the boundaries of vortex structures, and their time-variant direction ensures stress and strain transfer from the bulk of the loaded crystal to its peripheral free boundaries. When the strain goes above its critical value, such redistribution can lead to the formation of structural defects. Thus, the vortex structures formed by elastic atomic displacements can be considered as dynamic defects because they provide a way for internal relaxation in the loaded material.
Keywordsrotational motion dynamic defects shear deformation molecular dynamics strain redistribution structural defects
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The work was supported by Fundamental Research Program of the State Academies of Sciences for 2013–2020 (project No. III.23.2.4 project). The results related to lattice defect formation due to elastic stress redistribution were obtained under Russian Science Foundation grant No. 17-19-01374. The molecular dynamics simulation was performed on a Skif Cyberia supercomputer under Competitiveness Enhancement Program of Tomsk State University.
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