两相区退火温度对高铝低硅TRIP 钢组织性能的影响

对高铝低硅TRIP钢进行两相区退火，通过分析退火后实验钢的微观结构和力学性能，建立了加工硬化指数与相组成的关系，探讨了残余奥氏体稳定性对力学性能的影响.结果表明，随着两相区退火温度的升高，实验钢中贝氏体含量逐渐降低，残余奥氏体含量先增大后降低，并在930℃退火时达到最大.随着两相区退火温度的升高，实验钢的抗拉强度逐渐降低，延伸率先增大后降低，930℃退火时抗拉强度为665MPa，延伸率达到最大，为30%，强塑积约为20GPa·%.EBSD统计和拉伸试验的结果表明，两相区退火温度为930℃时，残余奥氏体稳定性适中，从而在拉伸过程中不断地提供加工硬化，推迟颈缩的发生，大幅度提高塑性.

Effect of Intercritical Annealing Temperature on Microstructure and Mechanical Property of High Al-Low Si TRIP Steel

The high Al-low Si TRIP steels were annealed at different intercritical temperatures. The microstructures and mechanical properties were examined to establish the relationship between work hardening exponent and phase components， and the effect of retained austenite stability on mechanical properties of tested steels were analyzed. The results show that， with the increase in intercritical annealing temperature， the content of bainite gradually decreased， while the volume fraction of retained austenite increased first and then decreased. The volume fraction of retained austenite reached largest when annealing temperature was 930℃. The tensile strength of experimental steel decreased with the increase of intercritical annealing temperature， and the elongation increased first and then decreased. When the annealing temperature was 930℃， the tensile strength was 665MPa， and the elongation reached its maximum of about 30%， and the resulting product of strength and elongation was approximately 20GPa·%. By combining EBSD analyses and tensile tests， it can be concluded that the retained austenite possessed moderate stability when the tested steel was annealing at 930℃， so that work hardening ability is continuously provided during tensile testing period. As a result， the plasticity of annealed TRIP steels had been improved.