Effect of Solution treatment on microstructure and mechanical properties of TWIP steel

Effect of solution temperature and time on microstructure,tensile properties and fractography of TWIP steel was studied by tensile test, optical microstructure, SEM and EDS, and phase composition was measured by X-ray diffraction. The results show that the effects of solution temperature and time on plasticity of TWIP steel is greater than that on strength. The optimized parameters with optimal elongation are solution treatment at 1000-1050 0°C for 60 min. Increasing solution temperature and time can be beneficial to both the generation of more annealing twins to increase their boundary areas and austenite grain growth. The fracture mechanism of TWIP steel is typical ductile fracture under the condition of tensile failure, and the microstructure is austenite with a large number of annealing twins before deformation. During tensile process, the annealing twins change into deformation twins, which make the plasticity of TWIP steel increase.