Assessment of the Strengthening Mechanisms Operating in Microalloyed Steels During Cyclic Deformation Using High-Resolution Electron Backscatter Diffraction

Abstract

Work hardening, grain boundary, substructure and texture strengthening are the most significant hardening mechanisms that influence the strength of microalloyed steels during deformation below non-recrystallization temperature. What is more, their mechanical response is a result of primary processing, where precipitation and solid solution strengthening play an important role. In practice, many room temperature metal forming operations involve cyclic strain path changes that introduce complex loading conditions. Thus, in the present work, the effects of cyclic strain reversal on microstructure and texture development in microalloyed steel were studied using room temperature torsion tests. High-resolution EBSD was used to analyse the microstructure and texture evolution at different stages of cyclic deformation. A similar analysis was also performed using low-carbon steel as a reference material. The analysis was focused on substructure formation and rotation mechanism as a result of strain reversal in both steels. Finally, conclusions regarding the effects of strain reversal on abovementioned strengthening mechanisms were drawn.