During the last decade severe plastic deformation (SPD) techniques have been successfully used for the fabrication of nanostructures in various bulk metallic materials. This paper presents several results from recent investigations of SPD materials focussing on two main objectives: - modelling and experimental works on SPD techniques, aimed at producing homogeneous nanostructures in bulk large-size billets and to process hard-to-deform and low-ductility materials; - establishing the influence of SPD parameters (strain amount, temperature, applied pressure, etc) on microstructural (types of grain boundaries, defect structures) features and properties in SPD-processed materials.