Erhart, P. ; Bringa, E. M. ; Kumar, M. ; Albe, K. (2005)
Atomistic mechanism of shock-induced void collapse in nanoporous metals.
In: Phys. Rev. B, 72 (5)
doi: 10.1103/PhysRevB.72.052104
Article, Bibliographie
Abstract
We have investigated the microstructural changes in ductile porous metals during high pressure-high strain rate loading employing atomistic simulations and explored their relation to recent experiments on polycrystalline copper samples. Molecular-dynamics simulations of shocks in porous, single-crystal samples show the formation of nanograins due to localized massive plastic deformation induced by the presence of voids. In the process of grain formation the individual voids serve as dislocation sources. The efficiency of these sources is further enhanced by their collective interaction which eventually leads to very high dislocation densities. In agreement with experimental studies, the simulations display a temporal delay of the particle velocity in comparison to perfectly crystalline samples. This delay increases with porosity. Our results point towards the importance of void-void interactions and collective effects during dynamic loading of porous materials.
| Item Type: | Article |
|---|---|
| Erschienen: | 2005 |
| Creators: | Erhart, P. ; Bringa, E. M. ; Kumar, M. ; Albe, K. |
| Type of entry: | Bibliographie |
| Title: | Atomistic mechanism of shock-induced void collapse in nanoporous metals |
| Language: | English |
| Date: | 5 August 2005 |
| Publisher: | American Physical Society |
| Journal or Publication Title: | Phys. Rev. B |
| Volume of the journal: | 72 |
| Issue Number: | 5 |
| DOI: | 10.1103/PhysRevB.72.052104 |
| URL / URN: | http://prb.aps.org/abstract/PRB/v72/i5/e052104 |
| Abstract: | We have investigated the microstructural changes in ductile porous metals during high pressure-high strain rate loading employing atomistic simulations and explored their relation to recent experiments on polycrystalline copper samples. Molecular-dynamics simulations of shocks in porous, single-crystal samples show the formation of nanograins due to localized massive plastic deformation induced by the presence of voids. In the process of grain formation the individual voids serve as dislocation sources. The efficiency of these sources is further enhanced by their collective interaction which eventually leads to very high dislocation densities. In agreement with experimental studies, the simulations display a temporal delay of the particle velocity in comparison to perfectly crystalline samples. This delay increases with porosity. Our results point towards the importance of void-void interactions and collective effects during dynamic loading of porous materials. |
| Divisions: | 11 Department of Materials and Earth Sciences > Material Science > Materials Modelling 11 Department of Materials and Earth Sciences > Material Science 11 Department of Materials and Earth Sciences |
| Date Deposited: | 28 Feb 2012 15:00 |
| Last Modified: | 31 Oct 2016 10:11 |
| PPN: | |
| Funders: | This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48., We would like to thank the ASCI-DOM program for partial financial support. |
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