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Molecular dynamics simulations of shock-induced plasticity in tantalum

Tramontina, Diego and Erhart, Paul and Germann, Timothy and Hawreliak, James and Higginbotham, Andrew and Park, Nigel and Ravelo, Ramón and Stukowski, Alexander and Suggit, Mathew and Tang, Yizhe and Wark, Justin and Bringa, Eduardo (2014):
Molecular dynamics simulations of shock-induced plasticity in tantalum.
In: High Energy Density Physics, Elsevier Science Publishing, pp. 9-15, 10, ISSN 15741818,
[Online-Edition: http://dx.doi.org/10.1016/j.hedp.2013.10.007],
[Article]

Abstract

We present Non-Equilibrium Molecular Dynamics (NEMD) simulations of shock wave compression along the [001] direction in monocrystalline Tantalum, including pre-existing defects which act as dislocation sources. We use a new Embedded Atom Model (EAM) potential and study the nucleation and evolution of dislocations as a function of shock pressure and loading rise time. We find that the flow stress and dislocation density behind the shock front depend on strain rate. We find excellent agreement with recent experimental results on strength and recovered microstructure, which goes from dislocations to a mixture of dislocations and twins, to twinning dominated response, as the shock pressure increases.

Item Type: Article
Erschienen: 2014
Creators: Tramontina, Diego and Erhart, Paul and Germann, Timothy and Hawreliak, James and Higginbotham, Andrew and Park, Nigel and Ravelo, Ramón and Stukowski, Alexander and Suggit, Mathew and Tang, Yizhe and Wark, Justin and Bringa, Eduardo
Title: Molecular dynamics simulations of shock-induced plasticity in tantalum
Language: English
Abstract:

We present Non-Equilibrium Molecular Dynamics (NEMD) simulations of shock wave compression along the [001] direction in monocrystalline Tantalum, including pre-existing defects which act as dislocation sources. We use a new Embedded Atom Model (EAM) potential and study the nucleation and evolution of dislocations as a function of shock pressure and loading rise time. We find that the flow stress and dislocation density behind the shock front depend on strain rate. We find excellent agreement with recent experimental results on strength and recovered microstructure, which goes from dislocations to a mixture of dislocations and twins, to twinning dominated response, as the shock pressure increases.

Journal or Publication Title: High Energy Density Physics
Volume: 10
Publisher: Elsevier Science Publishing
Uncontrolled Keywords: Tantalum, Molecular dynamics, Shocks
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: 19 Nov 2013 09:41
Official URL: http://dx.doi.org/10.1016/j.hedp.2013.10.007
Identification Number: doi:10.1016/j.hedp.2013.10.007
Funders: D. Tramontina and E.M. Bringa were funded by projects PICT2008-1325 from the ANCyT and 06/M035 from SecTyP-U.N. Cuyo. , A. Higginbotham acknowledges support from AWE., M. Suggit and J.S. Wark acknowledge support from EPSRC under grant P/J017256/1., R. Ravelo acknowledges support from the Air Force Office of Scientific Research under Award FA9550-12-1-0476., Work at Los Alamos was performed under the auspices of the U.S. Department of Energy (DOE) under Contract No. DE-AC52-06NA25396. P. Erhart acknowledges support from the Swedish Research Council (VR) and the Area of Advanced Materials at Chalmers.
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