ABSTRACT
The long-range internal stress fields (IS) play an important role in different processes taking place in ultrafine-grained materials produced by severe plastic deformation (SPD). Insufficient attention has been paid to these fields in experiments. Transmission electron microscopy (TEM) is the most suitable method for studying the internal stress fields. This chapter focuses on the methods of electron microscopic examination of the internal stress fields. It outlines the sources of the internal stress fields. The internal stresses provide a significant contribution to the deformation resistance for the formation and evolution of the defective structure and its rearrangement during deformation is closely linked with the relaxation of internal stresses. One of the most important problems in the investigations is the determination of the true grain size. This is carried out using the methods of transmission electron microscopy and X-ray diffraction analysis.
