Introduction

The present book deals with plastic deformation processes in the so-called nanocrystalline materials, a special type of deformed solid-state nanostructure which comprises a significant fraction of the general class of nanostructures. Typical examples of deformed solid-state nanostructures are bulk nanocrystalline metals and alloys, nanolayered heterostructures, nanocrystalline thin filins and coatings, etc. [6–8]. The most common feature of these structures is that they consist of small particles or layers which are separated by specific interfaces and have a characteristic size from 1 to 100 nanometers (1 nm = 10−9 in). The bottom limit of this range corresponds to some 2–4 interatomic distances in a solid, while the top limit is quite symbolic. In our previous book [8], we subdivided solid-state nanostructures into the ordered and disordered ones. For example, bulk nanocrystalline metals and alloys as well as nanocrystalline thin films may be classified as disordered nanostructures because the size of their nanograins (nanocrystallites) is a random quantity, not to mention the randomness of their shape, inhomogeneity in the chemical composition and defect structure across the sample. In contrast, due to peculiarities in their fabrication and function, high-quality nanolayered heterostructures may be classified as ordered nanostructures.