Paradoxes of severe plastic deformation

Severe plastic deformation (SPD) can lead to emergence of microstructural features and properties in materials which are fundamentally different form the ones well known for conventional cold deformation. In particular, the instances of unusual transformations resulting in development of highly metastable states associated with formation or supersaturated solid solutions, disordering or amorphization and their further decomposition during heating, high thermal stability of the SPD-produced nanostructures, and the paradox of strength and ductility in some SPD-processed metals and alloys are discussed.