The crystallite-size dependence of structural parameters in pure ultrafine-grained copper

Abstract

Quantitative x-ray diffraction investigations were performed on ultrafine-grained copper samples with various crystallite sizes processed by severe plastic deformation. In the x-ray diffraction patterns, common features such as the relative maximum intensity, considerable broadening, long tails, centroid positions of Bragg reflections shifted to larger diffraction angles and increased background integrated intensities are revealed. The evolution of the shape of the Bragg reflections, background integrated intensity, microstrain, dislocation density, lattice parameter and atomic displacement with decreasing crystallite size was investigated. The obtained results are analysed and discussed in terms of the structural model of ultrafine-grained materials processed by severe plastic deformation.