Atomistic simulation of shocks in single crystal and polycrystalline Ta

ORAL

Abstract

Non-equilibrium molecular dynamics (MD) simulations of shocks in Ta single crystals and polycrystals were carried out using up to 360 million atoms. Several EAM and FS type potentials were tested up to 150 GPa, with varying success reproducing the Hugoniot and the behavior of elastic constants under pressure. Phonon modes were studied to exclude possible plasticity nucleation by soft-phonon modes, as observed in MD simulations of Cu crystals. The effect of loading rise time in the resulting microstructure was studied for ramps up to 0.2 ns long. Dislocation activity was not observed in single crystals, unless there were defects acting as dislocation sources above a certain pressure.

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Authors

  • E.M. Bringa

    Conicet \& ICB, U. N. Cuyo, Universidad Nacional de Cuyo, Mendoza, Argentina, CONICET \& Instituto de Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza, Argentina, CONICET \& Instituto de Ciencias B\'asicas, Univ. Nac.Cuyo

  • Andrew Higginbotham

    University of Oxford, UK, Department of Physics, Clarendon Laboratory, University of Oxford

  • N. Park

    A.W.E., Aldermaston, Reading, RG7 4PR, UK

  • Yizhe Tang

    Department of Mechanical Engineering, University of California San Diego, University of California, San Diego

  • Matthew Suggit

    University of Oxford, UK, Department of Physics, Clarendon Laboratory, University of Oxford

  • Gabriele Mogni

    Department of Physics, Clarendon Laboratory, University of Oxford, University of Oxford, UK

  • C.J. Ruestes

    Instituto de Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza, Argentina

  • Jim Hawreliak

    LLNL, Lawrence Livermore National Laboratory

  • P. Erhart

    Lawrence Livermore National Laboratory

  • Marc Meyers

    UCSD, Department of Mechanical Engineering, University of California San Diego, University of California, San Diego

  • J.S. Wark

    Department of Physics, Clarendon Laboratory, University of Oxford