Effect of the cold rolling reduction on the microstructural characteristics and mechanical behavior of a 0.06%C-17%Mn TRIP/TWIP steel

High Mn steels, alloyed with Si and Al, present large plasticity when deformed due to the TRIP/TWIP effect. The present work studies the microstructural evolution and its influence on the mechanical behavior of a steel containing 17%Mn and 0.06%C after cold rolling to 45 and 90% reduction and subsequent annealing at 700 degrees C for different times. The microstructural analysis is performed by X-ray diffraction (XRD), scanning electronmicroscopy (SEM)-electron backscatter diffraction (EBSD), and transmission electronmicroscopy (TEM). It is observed that cold reduction induces the formation of epsilon- and alpha'-martensite. The material exhibits yield and tensile strength around 700 and 950 MPa, respectively, with a total elongation around 43% and a work hardening exponent of around 0.30 after 45% cold rolling and subsequent annealing and a yield and tensile strength of 750 and 950 MPa, respectively, with a total elongation of almost 50% when 90% cold rolling and subsequent annealing. The austenite texture contains brass, copper, and Goss components, while the alpha'- and epsilon-martensite textures mainly consist of rotated cube and prismatic and pyramidal fibers, respectively