Deformation of nanocrystalline materials by molecular-dynamics simulation: relationship to experiments?

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

doi:10.1016/j.actamat.2004.08.045

Cited by 664 publications

(366 citation statements)

References 144 publications

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“…MD simulation suggests itself as a natural approach for understanding the intrinsic mechanisms underlying the evolution of crystal defects [19][20][21][22][23][24]. To the best of our knowledge, the first MD simulation of dislocation was probably proposed by De Wette et al [25] in 1969.…”

Section: Introductionmentioning

confidence: 99%

How to identify dislocations in molecular dynamics simulations?

Wang

Yang

et al. 2014

Sci. China Phys. Mech. Astron.

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Dislocations are of great importance in revealing the underlying mechanisms of deformed solid crystals. With the development of computational facilities and technologies, the observations of dislocations at atomic level through numerical simulations are permitted. Molecular dynamics (MD) simulation suggests itself as a powerful tool for understanding and visualizing the creation of dislocations as well as the evolution of crystal defects. However, the numerical results from the large-scale MD simulations are not very illuminating by themselves and there exist various techniques for analyzing dislocations and the deformed crystal structures. Thus, it is a big challenge for the beginners in this community to choose a proper method to start their investigations. In this review, we summarized and discussed up to twelve existing structure characterization methods in MD simulations of deformed crystal solids. A comprehensive comparison was made between the advantages and disadvantages of these typical techniques. We also examined some of the recent advances in the dynamics of dislocations related to the hydraulic fracturing. It was found that the dislocation emission has a significant effect on the propagation and bifurcation of the crack tip in the hydraulic fracturing.

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Section: Introductionmentioning

confidence: 99%

How to identify dislocations in molecular dynamics simulations?

Wang

Yang

et al. 2014

Sci. China Phys. Mech. Astron.

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“…Recent molecular dynamics (MD) simulations have improved our understanding of the deformation of nanocrystalline materials [13]. The MD simulations in nanocrystalline copper [20][21][22][23], aluminum [11,24], nickel [22,23] and cobalt [25], where an inverse Hall-Petch effect was observed [11,17,20,21,[24][25][26], revealed the difference between the grain interior and the grain boundary regions where most of the deformation occurred due to the inter-grain deformation (sliding) mechanism [20,22,23,27,28]. It was further observed that the volume fraction of the total grain boundaries, which increases with decreasing grain size [29], increases under straining conditions, indicating an expansion of the grain boundary regions during straining [11].…”

Section: Introductionmentioning

confidence: 99%

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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“…[42,43] The results of MD simulations cannot be entirely applicable to the description of deformation in materials under typical experimental conditions, partly because simulations involve a limited number of grains and partly because they are performed at high strain rates (10 6 to 10 8 s À1 ) that are not typical of those associated with deformation experiments (10 À9 s À1 to 10 À2 s À1 ). However, recent analysis [48] has indicated that the results of MD have predicted several differences between CG and nc materials that are consistent with experimental evidence.…”

Section: Discussionmentioning

confidence: 53%

“…In the first approach, MD computer simulations were extensively used. [48] The MD simulations involving nc materials have revealed that as the grain size decreases, boundary sliding dominates. [42,43] The results of MD simulations cannot be entirely applicable to the description of deformation in materials under typical experimental conditions, partly because simulations involve a limited number of grains and partly because they are performed at high strain rates (10 6 to 10 8 s À1 ) that are not typical of those associated with deformation experiments (10 À9 s À1 to 10 À2 s À1 ).…”

Section: Discussionmentioning

confidence: 99%

Deformation Mechanisms in Nanocrystalline Materials

Mohamed

Yang

2009

Metall Mater Trans A

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As a result of recent investigations on nanocrystalline (nc) materials, extensive experimental data on the deformation behavior of these materials have become available. In this article, an analysis of these data was performed to identify the requirements that a viable deformation mechanism should meet in terms of accounting for the mechanical characteristics and trends that are revealed by the data. The results of the analysis show that a viable deformation mechanism is required to account for the following: (1) an activation volume the value of which is in the range 10 to 40 b 3 ; (2) an activation energy that is close to the activation energy for boundary diffusion but that decreases with increasing applied stress; (3) the magnitudes of deformation rates that cover wide ranges of temperatures, stresses, and grain sizes; (4) inverse Hall-Petch behavior; and (5) limited ductility. The validity of available deformation mechanisms for nc materials is closely examined in the light of these requirements.

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Deformation of nanocrystalline materials by molecular-dynamics simulation: relationship to experiments?

Cited by 664 publications

References 144 publications

How to identify dislocations in molecular dynamics simulations?

How to identify dislocations in molecular dynamics simulations?

Modeling the dependence of strength on grain sizes in nanocrystalline materials

Deformation Mechanisms in Nanocrystalline Materials

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