Molecular-dynamics study of mechanical properties of copper

Heino, P.; Häkkinen, Hannu; Kaski, Kimmo

doi:10.1209/epl/i1998-00142-5

Cited by 62 publications

(27 citation statements)

References 35 publications

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“…Note that the intragranular decohesion was not allowed in the model. In fact, according to studies [45] and [72], for a free copper crystal, applying a displacement perpendicular to the {011} planes leads to a maximum tensile strength of 14.97 and 14.3 GPa, respectively. These last values are higher than all σ c observed for the GB decohesion behavior predicted by QC simulations, so that no intragranular decohesion should be a priori expected.…”

Section: Two-scale Numerical Simulationsmentioning

confidence: 99%

A two-scale model predicting the mechanical behavior of nanocrystalline solids

Péron-Lührs

Jérusalem

Sansoz

et al. 2013

Journal of the Mechanics and Physics of Solids

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Polycrystalline materials, with nanosized grains (<100 nm), exhibit superior strength exceeding those of their coarse-grained counterparts. With such small grains, the deformation mechanisms taking place at grain boundaries (GBs) become dominant compared to the intragranular crystal plasticity. Recent studies have revealed that the deformation mechanisms are influenced by the GB network. For instance, a high yield stress in nanostructured metals can be obtained by choosing the relevant grain boundary character distribution (GBCD). In this paper we present an original numerical multiscale approach to predict the mechanical behavior of nanostructured metals according to their GBCD composed of either high angle (HA) GBs (HAB) or low angle (LA) GBs (LAB). Molecular simulations using the quasicontinuum method (QC) are performed to obtain the mechanical response at the nanoscale of GB undergoing simple shear (GB sliding behavior) and tensile loads (GB opening behavior). To simulate the grain behavior, a mechanical model of dislocation motions through a forest dislocation is calibrated using a nanoindentation simulation performed with QC. These QC results are then used in a finite element code (direct numerical simulation-DNS) as a GB constitutive model and as a grain constitutive model. This two-scale framework does not suffer from length scale limitations conventionally encountered when considering the two scales separately.

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Section: Two-scale Numerical Simulationsmentioning

confidence: 99%

A two-scale model predicting the mechanical behavior of nanocrystalline solids

Péron-Lührs

Jérusalem

Sansoz

et al. 2013

Journal of the Mechanics and Physics of Solids

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“…Other authors, as Heino et al, 38 use ab initio effective medium potentials for fcc copper. They find that both the Young's and shear moduli do not depend on the system size.…”

Section: Discussionmentioning

confidence: 99%

Surface effects in atomistic mechanical simulations of Al nanocrystals

2009

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Detailed knowledge of the mechanical properties of nanocrystals is crucial for understanding the behavior of micromachining devices. Determining experimentally the elastic and plastic properties of nanocrystals can be very challenging. In this work, we present molecular-dynamics simulations of mechanical properties of Al nanocrystals, both using Lennard-Jones and embedded-atom method potentials. We show that this kind of tests borrowed from mechanical engineering provide helpful insight on the mechanical behavior of nanocrystals. We also provide evidence suggesting that the small scale effects, mainly due to the small surface-to-volume ratio of nanocrystals, are crucial. The main results of our work are the failure of the thermodynamical relations connecting the applied stress and the material strain ͑additionally, we introduce a simple mathematical framework to account for this effect͒, the nonequilibrium behavior at the onset of the plastic deformation related to the appearance of long tails ͑power law͒ in the distribution of dissipated heat and, finally, the existence of conditions under which the system can experience reversible load-unload cycles in the plastic state.

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“…Therefore, compared with LS and MD simulation, the two-dimensional QC method is able to describe larger-scale atomic systems without the limitations of fixed or periodic boundary conditions encountered in classical molecular simulations and save considerable computing time while maintaining sufficient accuracy. 44,45 More details on the two-dimensional QC method can be found in Refs. 23-25. In the present study, the two-dimensional QC simulation of nanoindentation on Cu/Ag bilayer film system at zero temperature is performed to observe the misfit dislocation structure on interface and the interaction of nucleated dislocations with the misfit dislocations and the interface, as well as their influences on the mechanical response of nanoindentation.…”

Section: Methodsmentioning

confidence: 99%

Two-dimensional quasicontinuum analysis of the strengthening and weakening effect of Cu/Ag interface on nanoindentation

Mei

et al. 2010

Journal of Applied Physics

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Multiscale simulations using the two-dimensional quasicontinuum method are performed to understand the nature of strengthening and weakening effect of Cu/Ag interface on nanoindentation at zero temperature. The investigation shows that the upper Cu film strengthens distinctly the lower Ag substrate. The nucleation and emission for first dislocation in Cu film is postponed obviously due to the effect of interface. Combined with the dislocation theory, a dislocation model of the interaction between the nucleated dislocation and the misfit dislocation is introduced to systematically evaluate the strengthening and weakening effects of interface on the Cu/Ag bilayer film system. It is found that the strengthening effect of interface on nanoindentation is governed by the resistance to the nucleated dislocation transmission, such as image force, lattice friction, and the repulsive force of the misfit dislocation. The bigger resistance will lead to the stronger strengthening effect. The weakening effect is mainly produced by the stress concentration and local misfit strain in the core region of the misfit dislocations due to the nucleation and propagation of misfit dislocations along the interface. The multiscale simulation results are in good agreement with the experimental results and dislocation theory model.

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Molecular-dynamics study of mechanical properties of copper

Cited by 62 publications

References 35 publications

A two-scale model predicting the mechanical behavior of nanocrystalline solids

A two-scale model predicting the mechanical behavior of nanocrystalline solids

Surface effects in atomistic mechanical simulations of Al nanocrystals

Two-dimensional quasicontinuum analysis of the strengthening and weakening effect of Cu/Ag interface on nanoindentation

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