Defect and damage evolution during spallation of single crystal Al: Comparison between molecular dynamics and quasi-coarse-grained dynamics simulations

The links between loading orientation of single crystal Al and the dynamic evolution of defects (dislocations, twins, stacking faults etc.) during spallation are investigated using molecular dynamics (MD) simulations. The microstructural evolution during the shock compression of single crystal Al is observed to be primarily guided by the nucleation and evolution of Shockley partials and twin partials. The shock response and spallation behavior of single crystal Al is observed to be anisotropic and is influenced by the density of various types of dislocations during shock compression and void nucleation at the spall plane. The capability of the quasi-coarse-grained dynamics (QCGD) method to reproduce the MD predicted nucleation, interaction and evolution of dislocations during shock compression and spallation of single crystal Al is discussed. The QCGD method retains the relative contribution of different types of dislocations during propagation of shock compression wave, interactions of the wave and spallation of single crystal Al as predicted by MD using a fraction of representative atoms allowing the modeling of of larger sized systems for larger times. (C) 2017 Elsevier B.V. All rights reserved.