A characteristic feature of high-purity aluminum conductors is a high plasticity combined with large crystallites (≥ 1 mm). Low-temperature plastic deformation of these materials produces special features that are characteristic of both single crystals and fine-grain polycrystals. In this study, we investigated deformed polycrystals with different grain sizes and determined that the electrical and plastic properties of coarse-grain specimens are not simply values between those of single and polycrystals. At certain strains over the broad deformation range, large peaks in resistivity occurred that were correlated to large-grain orientation with respect to the deformation axis. Two plastic-deformation mechanisms based on the measured local deformation in the grains are discussed. The first mechanism is based on the assumption that high-density dislocation clusters exist in the near-boundary region; the second, on the possibility of grain rotation on the unstrengthened boundary.
展开▼
