Impact response of polycrystalline nickel: Experiments and molecular dynamics simulations

YF Sun and YT Chen and J Xu and WZ Wang and NB Zhang and YX Zhao and L Wang and Y Cai and L Lu and SN Luo, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 926, 147882 (2025).

DOI: 10.1016/j.msea.2025.147882

The dynamic mechanical properties and deformation/damage mechanisms of face centered cubic polycrystalline nickel are investigated systemically via plate impact experiments and molecular dynamics (MD) simulations. The Hugoniot equation of state and spall strength at peak shock stress up to 20 GPa are deduced from free surface velocity histories. The elastic-plastic transition is obscure with no evident Hugoniot elastic limit. The polycrystalline Ni exhibits low spall strength (similar to 1.6-2.0 GPa). Given the postmortem characterizations, plastic deformation is mainly achieved via dislocation glides. Ductile spallation is the main damage mode, and void nucleation occurs mostly at grain boundaries and triple junctions. The MD simulations reveal that intense shock compression can induce a < 110 > texture involving stacking faults, deformation twins and minor solid-solid phase transition. Due to the intense slip-GB intersections, intergranular damage are also predominant at different impact velocities. The evolution of the internal three-dimensional void damage characteristics are also analyzed. The present research provides valuable insights into impact response (mechanical properties and deformation mechanisms) and relationships between the microstructure characteristics and mechanical properties upon shock loading for polycrystalline Ni via both experiments and simulations.

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