Dislocation processes in the deformation of nanocrystalline aluminium by molecular-dynamics simulation

Yamakov, V.; Wolf, D.; Phillpot, Simon R.; Mukherjee, Amiya K.; Gleiter, H.

doi:10.1038/nmat700

Cited by 924 publications

(521 citation statements)

References 26 publications

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“…It is seen that the hardness in the nanoscale range increases with decreasing , and the value of d * increases with increasing . This is in agreement with the results of atomistic simulations of mechanical deformation [20,[38][39][40]. The simulation results suggested that grain boundary atoms as well as the atoms up to 7-10 lattice parameters away from the grain boundary are heavily involved in plastic deformation.…”

Section: Effect Of Effective Grain Boundary Thicknesssupporting

confidence: 89%

“…The traditional dislocation theories may no longer be applicable to the deformation behavior of nanocrystalline materials. Consistent with the recent experimental observations or models mentioned above, atomistic simulations also suggested that dislocations nucleated at grain boundaries (GBs) carry out plastic deformation in the nanocrystalline regime; once nucleated, these dislocations travel across the grains and are eventually absorbed in the opposite grain boundary [38][39][40]. In a very recent investigation on the plastic deformation recovery in nanocrystalline aluminum and gold films, it was reported that the enhancement of recovery rate could be due to the reduction in pinning sites caused by redistributions of grain boundary impurities during annealing [41].…”

Section: Introductionsupporting

confidence: 69%

“…in the grain boundary affected zone). In other words, the material near grain boundaries is easier to deform [20,[38][39][40] and the associated deformation mechanisms are also observed to be strain rate sensitive [37]. As a result, when the effective grain boundary thickness (or the grain boundary affected zone) decreases, the deformation becomes more limited and difficult, thus the hardness in the nanoscale regime increases with decreasing .…”

Section: Effect Of Effective Grain Boundary Thicknessmentioning

confidence: 99%

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Modeling the dependence of strength on grain sizes in nanocrystalline materials

Bhole

Chen

2008

Science and Technology of Advanced Materials

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A model was developed to describe the grain size dependence of hardness (or strength) in nanocrystalline materials by combining the Hall-Petch relationship for larger grains with a coherent polycrystal model for nanoscale grains and introducing a log-normal distribution of grain sizes. The transition from the Hall-Petch relationship to the coherent polycrystal mechanism was shown to be a gradual process. The hardness in the nanoscale regime was observed to increase with decreasing grain boundary affected zone (or effective grain boundary thickness, ) in the form of −1/2 . The critical grain size increased linearly with increasing . The variation of the calculated hardness value with the grain size was observed to be in agreement with the experimental data reported in the literature.

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Section: Effect Of Effective Grain Boundary Thicknesssupporting

confidence: 89%

Section: Introductionsupporting

confidence: 69%

Section: Effect Of Effective Grain Boundary Thicknessmentioning

confidence: 99%

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Modeling the dependence of strength on grain sizes in nanocrystalline materials

Bhole

Chen

2008

Science and Technology of Advanced Materials

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“…Considering the initial FCC order of Ni nanowire, here we define only three categories of atoms: 'FCC' atoms, having a local FCC order and considered to be inside the nanowires; 'HCP' atoms, having a local HCP order and classified as stacking faults; and 'other' atoms, all the other atoms considered as belonging to surface. The CNA method has already been used successfully to analyse the structural evolution during the deformation and melting process [32][33][34].…”

Section: Simulation Processmentioning

confidence: 99%

The uniaxial tensile deformation of Ni nanowire: atomic-scale computer simulations

Zhu

Shao

et al. 2005

Physica E: Low-dimensional Systems and Nanostructures

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The mechanical deformations of nickel nanowire subjected to uniaxial tensile strain at 300 K are simulated by using molecular dynamics with the quantum corrected Sutten-Chen many-body force field. We have used common neighbor analysis method to investigate the structural evolution of Ni nanowire during the elongation process. For the strain rate of 0.1%/ps, the elastic limit is up to about 11% strain with the yield stress of 8.6 GPa. At the elastic stage, the deformation is carried mainly through the uniform elongation of the distances between the layers (perpendicular to the Z-axis) while the atomic structure remains basically unchanged. With further strain, the slips in the {1 1 1} planes start to take place in order to accommodate the applied strain to carry the deformation partially, and subsequently the neck forms. The atomic rearrangements in the neck region result in a zigzag change in the stress-strain curve; the atomic structures beyond the region, however, have no significant changes. With the strain close to the point of the breaking, we observe the formation of a one-atom thick necklace in Ni nanowire. The strain rates have no significant effect on the deformation mechanism, but have some influence on the yield stress, the elastic limit, and the fracture strain of the nanowire. r

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“…MD simulations have also been performed to capture the nanoscale plastic deformation of polycrystalline materials. [12][13][14] Focusing on the specific grain boundaries in our previous study, density functional theory calculations have been applied to evaluate the fault energies of the twin and several CSL grain boundaries, and molecular statics (MS) simulations are performed incipient plastic event on the twin and CSL grain boundaries. 15) In the present study, we constructed two-dimensional thin film model and investigated the deformation characteristics of polycrystalline metal using MS simulations.…”

Section: Introductionmentioning

confidence: 99%

Atomistic Simulations of Stress Concentration and Dislocation Nucleation at Grain Boundaries

Tsuru

Kaji

Tsukada

et al. 2011

Progress in Nuclear Science and Technology

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Dislocation channeling observed in irradiated metals has been thought to be one of the key stress factors in irradiation assisted stress corrosion cracking since it is an evidence to suggest that the slip deformation is localized and that the strong misfit are generated at grain boundaries. In the present study, the stress concentration and defect nucleation of polycrystalline copper thin film is investigated by parallel molecular statics simulations. Uniaxial tensile deformation is applied to the two-dimensional polycrystalline model. As a result, it is found that the stress concentration is observed at triple point of grain junctions in the elastic and initial stage of plastic deformation. Then partial dislocations are first generated from the small angle grain boundaries. Twin deformations occur at triple points and grain boundaries which result in both another site of stress concentration around grain boundaries and local displacement relevant to the Burgers vector at grain boundary. One distinguishing characteristic of deformation mode of polycrystal is that the stress distribution strongly correlated with the presence of the partial dislocations and twin boundaries. Stress relaxation within each grain is preferentially brought about by the dislocation nucleation and twin deformation.

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Dislocation processes in the deformation of nanocrystalline aluminium by molecular-dynamics simulation

Cited by 924 publications

References 26 publications

Modeling the dependence of strength on grain sizes in nanocrystalline materials

Modeling the dependence of strength on grain sizes in nanocrystalline materials

The uniaxial tensile deformation of Ni nanowire: atomic-scale computer simulations

Atomistic Simulations of Stress Concentration and Dislocation Nucleation at Grain Boundaries

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