Microstructural evolution and nanocrystal formation during deformation of Fe-C alloys

The microstructural evolution has been investigated under different plastic deformation processes, which produce nanocrystalline structures from coarse-grained crystalline materials. Fe-C alloys were selected due to their popular application in industry and submitted to the deformation induced nanocrystallization processes. The investigation revealed that grain refinement to submicron level during deformation is related to the production of dislocations and their transformation to subgrain boundaries at low strain levels. The further refinement to a nanocrystalline structure is realized with the aid of high strain rates, which lead to the production of high densities of dislocations in a short time period to form nanoscaled cells and subgrain boundaries. These transform into nanocrystalline grain boundaries via the possible dynamic recovery and/or recrystallization processes induced by adiabatic heating at localized deformed regions. (C) 2003 Published by Elsevier B.V.