Shock-induced dynamic response in single and nanocrystalline high-entropy alloy FeNiCrCoCu

•The plastic deformation of the single-crystal sample along [001] direction is dominated by nanotwins and dislocation slip.•The plastic deformation of the single-crystal sample along [110] and [111] directions are attributed to the dislocation slip.•The spall defects of nanocrystalline display a heterogeneous nucleation mechanism at grain boundaries.