Atomistic mechanism of grain boundary sliding with the example of a large-angle boundary 2=5. Molecular dynamics calculation

2011 ◽  
Vol 14 (1-2) ◽  
pp. 24-31 ◽  
Author(s):  
A.I. Dmitriev ◽  
A.Yu. Nikonov ◽  
S.G. Psakhie
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Large Angle ◽  
Grain Boundary Sliding ◽  
Boundary Sliding ◽  
Dynamics Calculation ◽  
Large Angle Boundary

scholarly journals Deformation Behavior of Nanocrystalline Body-Centered Cubic Iron with Segregated, Foreign Interstitial: A Molecular Dynamics Study

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5351
Author(s):  
Ahmed Tamer AlMotasem ◽  
Matthias Posselt ◽  
Tomas Polcar
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Deformation Behavior ◽  
Large Scale ◽  
Grain Boundary Sliding ◽  
Carbon And Nitrogen ◽  
Embedded Atom ◽  
Boundary Sliding ◽  
Dynamics Simulations

In the present work, modified embedded atom potential and large-scale molecular dynamics’ simulations were used to explore the effect of grain boundary (GB) segregated foreign interstitials on the deformation behavior of nanocrystalline (nc) iron. As a case study, carbon and nitrogen (about 2.5 at.%) were added to (nc) iron. The tensile test results showed that, at the onset of plasticity, grain boundary sliding mediated was dominated, whereas both dislocations and twinning were prevailing deformation mechanisms at high strain. Adding C/N into GBs reduces the free excess volume and consequently increases resistance to GB sliding. In agreement with experiments, the flow stress increased due to the presence of carbon or nitrogen and carbon had the stronger impact. Additionally, the simulation results revealed that GB reduction and suppressing GBs’ dislocation were the primary cause for GB strengthening. Moreover, we also found that the stress required for both intragranular dislocation and twinning nucleation were strongly dependent on the solute type.

scholarly journals On the deformation-induced grain rotations in gradient nano-grained copper based on molecular dynamics simulations

2021 ◽  
Vol 10 (1) ◽  
pp. 87-98
Author(s):  
Jiarui Zhang ◽  
Fan Yang ◽  
Yaping Liu ◽  
Zheng Zhong ◽  
Jinfeng Zhao
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Molecular Dynamics Simulations ◽  
Grain Boundary Sliding ◽  
Effect Of Temperature ◽  
Uniaxial Deformation ◽  
Grain Rotation ◽  
Activation Theory ◽  
Boundary Sliding ◽  
Dynamics Simulations

Abstract In this paper, the mechanical behavior of gradient nano-grained copper under uniaxial deformation was investigated using molecular dynamics simulations. The stress response was found to be different in the regions with different grain sizes, which was attributed to the different dislocation activities due to the dislocation-grain boundary synergies. The phenomenon of grain rotation was observed and a program was developed to accurately evaluate the grain rotation and explore its dependence on the grain size and the initial crystal orientation. It is found that all grains tend to rotate to the 30° orientation, consistent with the activation theory of the slip systems under the uniaxial deformation. The rotation magnitude is larger for larger grains, but the rotation rate is more diversely distributed for smaller grains, indicating more disturbance from grain boundary mechanisms such as the grain boundary sliding and the grain boundary diffusion for smaller grains. The effect of temperature on the grain rotation is also investigated, showing an increase of the dispersion of grain rotation distribution with the increase of temperature. This paper aims at providing insights into the synergistic deformation mechanisms from dislocations and grain boundaries accounting for the exceptional ductility of the gradient nano-grained metals.

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