Microstructure and hardness evolution during isothermal process at 700 °C for Fe–24Mn–0.7Si–1.0Al TWIP steel

The microstructure and hardness evolution of Fe–24Mn–0.7Si–1.0Al TWIP steel during recrystallization were investigated by annealing the alloy at 700 °C for different time. The deformed structure is replaced by the equiaxed grains during recrystallization. The hardness decreased significantly in the first 5 min period and then slowly. The disappearance of the dislocation and microtwins plays a much greater role than the grain coarsening on the decrease of hardness.