Atomistic shock Hugoniot simulation of single-crystal copper

Abstract

Planar shock waves in single-crystal copper were simulated using nonequilibrium molecular dynamics with a realistic embedded atom potential. The simulation results are in good agreement with new experimental data presented here, for the Hugoniot of single-crystal copper along ⟨100⟩. Simulations were performed for Hugoniot pressures in the range 2 GPa – 800 GPa, up to well above the shock induced melting transition. Large anisotropies are found for shock propagation along ⟨100⟩,⟨110⟩, and ⟨111⟩, with quantitative differences from pair potentials results. Plastic deformation starts at Up≳0.75km∕s, and melting occurs between 200 and 220 GPa, in agreement with the experimental melting pressure of polycrystalline copper. The Voigt and Reuss averages of our simulated Hugoniot do not compare well below melting with the experimental Hugoniot of polycrystalline copper. This is possibly due to experimental targets with preferential texturing and/or a much lower Hugoniot elastic limit.

Shock Hugoniot of single crystal copper

“…Cu is an example of a anisotropic solid that has been the subject of some recent interest because of the large anisotropy ratio, A = 2c 44 /(c 11 -c 12 ) = 3.21, as calculated from the elastic stiffness constants, c ij . Using simple arguments, Bringa and co-workers suggested that a strong crystal orientation dependence would appear in both the elastic and plastic waves in Cu [4]. Using molecular dynamics (MD) simulations, Bringa et al [4] show a distinct deviation of the Hugoniot from the experimental polycrystalline data of Mitchell et al [6].…”

Shock response of nanotwinned copper from large-scale molecular dynamics simulations

“…Previous MD studies on the shock response of Cu were mostly limited on either single-crystal or twin-free nanocrystalline (NC) metals. [6][7][8][9][10]12,13,[17][18][19][20]22,27 Germann et al 6,7 and Bringa et al 9 studied the shock propagation along the low index directions of [001], [110], and [111] for single-crystal Cu by using Lennard-Jones (LJ) potentials and embedded atom method (EAM) potentials, respectively. The shock-induced plasticity from their results was quite similar qualitatively.…”

“…However, recent advancements using laser-induced shock compression allow the ability to reach strain rates up to 10 10 s −1 . [3][4][5] Most of the shock experiments are aimed at evaluating the macroscopic mechanical properties, such as the shock front structure, the shock Hugoniot, the strength behind the shock front, and spall strength. However, the dynamic response of materials induced by shock wave loading is often strongly dependent on microstructure evolutions and the underlying physics of deformation mechanisms.…”

Prediction of Coherent Optical Radiation from Shock Waves in Polarizable Crystals

“…[5]) propagating through crystalline NaCl. Such commonly utilized simulations solve the classical equations of motion for atoms subject to an empirically-constructed interaction potential and incorporate thermal effects and deformation of the crystal lattice.…”