Structure of Iron Deformed at 250°С by Torsion under a Pressure

Abstract

Transmission electron microscopy and scanning electron microscopy were used to study the evolution of the structure of iron (of 99.97% purity) in the course of deformation at 250°С by torsion under pressure. Electron back-scattered diffraction analysis was used to determine the size of recrystallized grains, their orientation, angular range of grain-boundary misorientation, and fraction of recrystallized structure. It was found that, upon deformation at 250°С by torsion under a pressure, the dynamic recrystallization of iron starts on reaching the true strain е = 2.4. At the steady stage of deformation, the structure with an average grain size of 0.5 µm forms, which is characterized by the absence of any preferential orientation.