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Plastic deformation of a porous bcc metal containing nanometer sized voids

Ruestes, C. J. and Bringa, E. M. and Stukowski, A. and Rodríguez Nieva, J. F. and Tang, Y. and Meyers, M. A. (2014):
Plastic deformation of a porous bcc metal containing nanometer sized voids.
In: Computational Materials Science, Elsevier Science Publishing, pp. 92-102, 88, ISSN 09270256,
[Online-Edition: http://dx.doi.org/10.1016/j.commatsci.2014.02.047],
[Article]

Abstract

Nanoporous materials, can present an outstanding range of mechanical properties. Both molecular dynamics and dislocation analysis were used to evaluate and quantify the evolution of plasticity in a porous Ta single crystal containing randomly placed voids with 3.3 nm radii and average initial porosity of 4.1%, when subjected to uniaxial compressive strain. Nanovoids act as effective sources for dislocation emission. Dislocation shear loops nucleate at the surface of the voids and expand by the advance of the edge component. The evolution of dislocation configuration and densities were predicted by the molecular dynamics calculations and successfully compared to an analysis based on Ashby’s concept of geometrically-necessary dislocations. Resolved shear stress calculations were performed for all bcc slip systems and used to identify the operating Burgers vectors in the dislocation loops. The temperature excursion during plastic deformation was used to estimate the mobile dislocation density which is found to be less than 10% of the total dislocation density.

Item Type: Article
Erschienen: 2014
Creators: Ruestes, C. J. and Bringa, E. M. and Stukowski, A. and Rodríguez Nieva, J. F. and Tang, Y. and Meyers, M. A.
Title: Plastic deformation of a porous bcc metal containing nanometer sized voids
Language: English
Abstract:

Nanoporous materials, can present an outstanding range of mechanical properties. Both molecular dynamics and dislocation analysis were used to evaluate and quantify the evolution of plasticity in a porous Ta single crystal containing randomly placed voids with 3.3 nm radii and average initial porosity of 4.1%, when subjected to uniaxial compressive strain. Nanovoids act as effective sources for dislocation emission. Dislocation shear loops nucleate at the surface of the voids and expand by the advance of the edge component. The evolution of dislocation configuration and densities were predicted by the molecular dynamics calculations and successfully compared to an analysis based on Ashby’s concept of geometrically-necessary dislocations. Resolved shear stress calculations were performed for all bcc slip systems and used to identify the operating Burgers vectors in the dislocation loops. The temperature excursion during plastic deformation was used to estimate the mobile dislocation density which is found to be less than 10% of the total dislocation density.

Journal or Publication Title: Computational Materials Science
Volume: 88
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Molecular dynamics, Dislocations, Nanoporous, Nanovoid
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: 11 Sep 2014 07:41
Official URL: http://dx.doi.org/10.1016/j.commatsci.2014.02.047
Identification Number: doi:10.1016/j.commatsci.2014.02.047
Funders: C.J.R. thanks support from a PFDT scholarship and by UC Laboratories Research Program 12-LR-239079., E.M.B. thanks support from grant PICT2009-0092 and SeCTyP-UNCuyo., Y.T. and M.A.M. thank the UC Research Laboratories Grant 09-LR-118456.
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