固溶处理对TWIP钢组织和力学性能的影响

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

用拉伸试验、金相观察、SEM和EDS等方法研究固溶温度和时间对TWIP钢微观组织、拉伸性能及断口形貌的影响,并采用X射线衍射仪测定材料的物相组成。结果表明,固溶温度和时间对TWIP钢塑性的影响程度明显大于强度,伸长率最佳的固溶处理工艺为1000-1050℃固溶60 min。随固溶温度的升高和固溶时间的延长,奥氏体晶粒长大,退火孪晶数量和退火孪晶界面积增加。拉伸时发生典型的延性断裂,拉伸前的组织为伴有大量退火孪晶的奥氏体,在拉伸过程中退火孪晶转变成形变孪晶,使TWIP钢的塑性提高。

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 ℃ 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.