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Anisotropic shock response of columnar nanocrystalline Cu

Luo, Sheng-Nian and Germann, Timothy C. and Desai, Tapan G. and Tonks, Davis L. and An, Qi (2010) Anisotropic shock response of columnar nanocrystalline Cu. Journal of Applied Physics, 107 (12). Art. No. 123507. ISSN 0021-8979. https://resolver.caltech.edu/CaltechAUTHORS:20100809-143256112

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Abstract

We perform molecular dynamics simulations to investigate the shock response of idealized hexagonal columnar nanocrystalline Cu, including plasticity, local shear, and spall damage during dynamic compression, release, and tension. Shock loading (one-dimensional strain) is applied along three principal directions of the columnar Cu sample, one longitudinal (along the column axis) and two transverse directions, exhibiting a strong anisotropy in the response to shock loading and release. Grain boundaries (GBs) serve as the nucleation sites for crystal plasticity and voids, due to the GB weakening effect as well as stress and shear concentrations. Stress gradients induce GB sliding which is pronounced for the transverse loading. The flow stress and GB sliding are the lowest but the spall strength is the highest, for longitudinal loading. For the grain size and loading conditions explored, void nucleation occurs at the peak shear deformation sites (GBs, and particularly triple junctions); spall damage is entirely intergranular for the transverse loading, while it may extend into grain interiors for the longitudinal loading. Crystal plasticity assists the void growth at the early stage but the growth is mainly achieved via GB separation at later stages for the transverse loading. Our simulations reveal such deformation mechanisms as GB sliding, stress, and shear concentration, GB-initiated crystal plasticity, and GB separation in nanocrystalline solids under shock wave loading.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1063/1.3437654 DOIArticle
http://jap.aip.org/japiau/v107/i12/p123507_s1PublisherArticle
ORCID:
AuthorORCID
An, Qi0000-0003-4838-6232
Additional Information:© 2010 American Institute of Physics. Received 30 March 2010; accepted 4 May 2010; published online 16 June 2010. This work is supported by the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory (Project No. LDRD-20090035DR). LANL is operated by Los Alamos National Security, LLC for the U.S. Department of Energy under Contract No. DEAC52-06NA25396. We have benefited from valuable discussions with A. Koskelo, P. Peralta, B. Holian, B. Uberuaga, C. Barnes, and other colleagues.
Funders:
Funding AgencyGrant Number
Los Alamos National LaboratoryLDRD-20090035DR
Department of Energy (DOE)DE-AC52-06NA25396
Subject Keywords:copper, crystallographic shear, grain boundaries, grain size, molecular dynamics method, nanostructured materials, nucleation, plasticity, shear deformation, shock waves, voids (solid)
Issue or Number:12
Classification Code:PACS: 61.46.Df; 62.20.F-; 61.72.Qq; 61.72.Mm; 81.40.Lm; 61.72.-y; 62.50.Ef
Record Number:CaltechAUTHORS:20100809-143256112
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20100809-143256112
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:19349
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Aug 2010 22:00
Last Modified:03 Oct 2019 01:55

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