The structure–property relationship was studied in an Fe-18Mn-0.6C-1.5Al steel subjected to cold rolling to various total reductions from 20% to 80% and subsequent annealing for 30 min at temperatures of 673 to 973 K. The cold rolling resulted in significant strengthening of the steel. The hardness increased from 1900 to almost 6000 MPa after rolling reduction of 80%. Recovery of cold worked microstructure developed during annealing at temperatures of 673 and 773 K, resulting in slight softening, which did not exceed 0.2. On the other hand, static recrystallization readily developed in the cold rolled samples with total reductions above 20% during annealing at 873 and 973 K, leading to fractional softening of about 0.8. The recrystallized grain size depended on annealing temperature and rolling reduction; namely, it decreased with a decrease in the temperature and an increase in the rolling reduction. The mean recrystallized grain size from approximately 1 to 8 μm could be developed depending on the rolling/annealing conditions. The recovered and fine grained recrystallized steel samples were characterized by improved strength properties. The yield strength of the recovered, recrystallized, and partially recrystallized steel samples could be expressed by a unique relationship taking into account the fractional contributions from dislocation and grain size strengthening into overall strength.

Effect of cold rolling on the microstructure and mechanical properties of a Fe-23Mn-0.3C-1.5Al (in wt. %) TWIP steel with an initial grain size of 24 μm was studied. Extensive deformation twinning occurred upon reduction by rolling. The volume fraction of the deformation twins attained about 0.2 at a reduction of 20%. Then, the intensity of deformation twinning gradually decreased with increasing the total rolling reduction. The average twin thickness of about 20 nm remained unchanged, although the distance between twins progressively reduced with increasing strain. The deformation banding was observed after a reduction of 60%. The thickness and volume fraction of microshear bands increased with increasing rolling reduction. The cold rolling led to significant strengthening of the steel that is accompanied by a drop on ductility. The yield stress (YS) increased from 235 MPa in the initial state to 1400 MPa after cold rolling with a reduction of 80%, whereas the elongation to failure decreased from 96% to 4%, respectively.

A physically based model is applied to evaluate the tensile behavior of high-Mn TWIP steel. Tensile tests are interrupted after 20, 40, 60, and 80% deformation and the kernel average misorientation method is used to estimate the dislocation density in each condition. It is found that the dislocation density evolution can be described by the exponential law, but the tensile behavior cannot be described only by dislocation strengthening. A reduction of the mean free dislocation path due to the formation of mechanical twins is considered as the strengthening contribution. The tensile curve is found to include three strengthening terms: friction stress, dislocation-dislocation interaction, and dislocation-boundary interaction, and the calculated curve is in good agreement with the experiment.