Microstructure and tensile deformation of nanocrystalline Cu produced by pulse electrodeposition

Bulk nanocrystalline Cu with an average grain size of 33 nm, a strong {2 0 0} texture and a narrow grain size distribution was produced by pulse electrodeposition. Tensile tests on this material indicated a combination of high yield strength (624 MPa), limited tensile elongation (<5%) and enhanced strain rate sensitivity (0.029). Deformation mechanisms were discussed with strain rate sensitivity and activation volume under analytical models from the literature. Overall, the plastic deformation of the nanocrystalline Cu was dominated by dislocation processes, while grain boundary activities were also involved especially at the lowest strain rate. Analysis on the fracture surfaces revealed a brittle feature.