Abstract
Over the last two decades it was well documented that the formation of ultrafine-grained (UFG) structures with the grain sizes in submicron (< 1 μm) or nanometer (< 100 nm) range in metallic materials increases strength but typically also leads to decrease in ductility. However, recent studies demonstrated that extraordinarily high strength and enhanced ductility can be obtained in the UFG metals and alloys when it is possible to control not only grain sizes but also the formation of various nanostructured elements, such as nanoparticles, nanotwins and grain boundary structures (states) by means of severe plastic deformation (SPD) techniques. These new trends applied to different metallic materials with superior strength and high ductility are considered and discussed in the present paper.
