Shock induced deformation response of single crystal copper: Effect of crystallographic orientation

We have carried out multimillion atom non-equilibrium molecular dynamics simulations for investigating the effect of crystallographic orientation over the evolution of deformation pathway of single crystal copper under shock compression. Based on symmetry, three different crystallographic directions, < 100 >, < 110 > and < 111 > are selected and taken as shock directions. Shock Hugoniot points has been calculated and compared among these different directions up to similar to 450 GPa of shock pressure i.e. piston velocity of 3.0 km/s. Orientational anisotropy has been observed for the bulk Cu single crystals shock loaded along these three different directions. Even though this feature may not show up explicitly in experimental investigations which typically measures shock-velocity and density Hugoniot curve, it is apparent from large scale atomistic simulations which measures the temperature Hugoniot curve quite accurately. Differences are observed in the von-Mises strain and stress plot distributions for shock loading of different intensities along the three directions. Large directional dependency is also evident in the evolution mechanism of deformation. Temperature profiles at different piston velocities for the shock front and the shock equilibrated regions shows significantly different and interesting patterns along the three orientations. Maxwell-Boltzmann distribution is observed in the atomic velocities (thereby the temperature profiles also) for both the shock front region as well as the shock equilibrated region for shock loading along all the three directions. (C) 2017 Elsevier B.V. All rights reserved.