Influence of cold deformation on microstructure, crystallographic orientation and tensile properties of an experimental austenitic Fe–26Mn-0.4C steel

The correlation between microstructure, crystallographic orientation and grain boundaries characteristics of an austenitic high manganese steel was systematically investigated. The as-received and cold-rolled specimens with 50% and 70% reduction were analyzed using Scanning Electron Microscopy (SEM), Electron Back-Scattered Diffraction (EBSD) and X-ray diffraction techniques. A significant increase in the fraction of low-energy S3 twin boundaries, from 16.21% to 24.41%, was found in the 70% deformed sample. This was coupled with the formation of {011} austenitic structure, and occurrence of twinning-induced plasticity. The ductile-brittle fracture mode observed in the 70% cold rolled sample, which can be attributed to the formation of the high fraction of low-energy S3 twin boundaries, minimized both the localized stored strain energy and lattice misfit and promoted dislocation glide. A potential employment of the investigated steel in the petroleum industry is discussed.