Effects of Cold Rolling and Annealing on Microstructure and Tensile Deformation Behavior of Fe-12Mn-7Al-0.2C-0.6Si Steel

The cold-rolled Fe-12Mn-7Al-0.2C-0.6Si steel was annealed, and the effect of annealing temperatures on the tensile properties of the steel was studied. The microstructure and tensile deformation behavior of the steel were investigated by OM, XRD and EBSD techniques. The results show that there are two phases of austenite and ferrite in the microstructure of the steel after cold-rolled and annealing. The content of austenite phase increases with increasing annealing temperature. The yield and tensile strength decrease, and the plasticity increases with increasing annealing temperature. At the beginning of the tensile deformation, the strain is mainly concentrated in austenite phase, and the strain transfers to ferric phase at high strain range. Considering the proportion of the two phases and the segregation of Al and Mn, the stacking fault energy of austenite phase after annealing at 800℃ is calculated to be 40.4 m J/m2. Therefore, the dislocation slip is the deformation mechanism of austenite phase.