Effect of Deformation Temperature on Tensile Deformation Behavior of Fe-20Mn-3Cu-1.3C TWIP Steel

The effect of deformation temperature on the mechanical properties and deformation mechanism of Fe-20Mn-3Cu-1.3C twinning induced plasticity (TWIP) steel when deformed at -100-200 'C was analysed by temperature controlled tensile tests. The microstructure of tensile samples was observed and analysed, and then the effect between stacking fault energy of TWIP steels and deformation temperature was calculated by thermodynamic model. The results show that with the deformation temperature increasing from -100 degree C to 200 degree C, the stacking fault energy of this steel gradually increases, but the volume fraction of twins gradually decreases. The tensile strength and yield strength will gradually decline, while the elongation of this steel firstly increases, then decreases. Furthermore, in this process, the plastic strain mechanism is transformed from twinning to slipping. The stacking fault energy gamma (SFE) is calculated by the equation gamma (SFE)=26.73+9.38x10(-2)T+4.22x10(-4)T(2)-4.47x10(-7)T(3). As com