Heterogeneous deformations in copper single crystals at high and low strain rates

Abstract In polycrystalline materials, the microscopic strain field is always highly heterogeneous during inelastic deformation, even when the macroscopic strain field is uniform. This is particularly true near potential damage and failure nucleation sites, such as voids and inclusions. Also, in the context of high-strain-rate plastic flow, the only currently practical way to induce large strains and high strain rates simultaneously under experimental conditions is by means of heterogenous deformations. For these and other reasons, experiments involving highly heterogeneous deformations are of considerable interest. A joint experimental/computational study of heterogeneous deformations in copper single crystals will be presented. Carefully oriented, monocrystalline copper specimens were subjected to large-strain indentation at both high and low strain rates. The high-rate experiments were performed using a split Hopkinson pressure bar high-strain-rate apparatus. Scanning and transmission electron microsco...