Ultrafine-grain metals by severe plastic deformation

•A tutorial review on UFG materials produced by severe plastic deformation•Deformation processes, microstructure, and material strength are examined.•Deformation mechanisms, dynamic recrystallization, and modeling are presented.

As a relatively simple top–down technique to produce nanomaterials in bulk, severe plastic deformation became a new way of transforming the microstructure of the material. When carried out at sufficiently low temperature, extreme large plastic deformations lead to ultrafine-grain or nearly nano-structured material. The aim of the present tutorial review is to give basic insight into the field of ultrafine-grain materials obtained by severe plastic deformation. The main features of the obtained microstructures are presented, the most important advantage of ultrafine-grain materials – an enhanced mechanical strength with respect to their coarse grained counterparts – is discussed. The operating deformation mechanisms that lead to the grain refinement are also examined. Finally, dynamic recrystallization which produces the ultrafine-grain structure is characterized and the main results of modeling efforts reproducing the grain refinement and several microstructure features are presented.