中文摘要：

利用实验室MMS-200热模拟试验机对Fe-0.2C-7Mn-3Al钢的临界区奥氏体稳定化行为进行研究.通过SEM,EPMA,TEM和XRD等手段观察并分析了实验钢的微观组织演变以及C和Mn元素的配分过程.实验结果表明,不同的临界区退火温度下,实验钢中均存在25%~30%左右的粗大压扁状δ铁素体.随着退火温度的升高,微观组织中残余奥氏体的含量先增加后减小,体积分数为10.2%~32.5%,残余奥氏体与临界区铁素体呈板条状相间分布,板条宽度约200~300 nm.最佳的临界区退火温度为750℃.C,Mn,Al元素的协同作用促进了临界区奥氏体的稳定化,使得实验钢能够在较短的时间内完成有效的配分.

英文摘要：

The intercritical austenite stabilization of Fe-0. 2C-7Mn-3Al steel was investigated by MMS-200 thermo-mechanical test machine in the lab. The microstructure evolution and the partitioning process of C,Mn were characterized and analyzed by using SEM,EPMA,TEMand XRD. The results showthat there are always 25%- 30% bulky flattened ferrite at different intercritical annealing temperatures. As the intercritical annealing temperature increases, the retained austenite content in the microstructure increases first and then decreases,with the volume fraction being 10. 2%- 32. 5%. The retained austenite and the intercritical ferrite are located with the lath shape,and the lath width is 200- 300 nm. The optimized annealing temperature is750 ℃. The synergistic effect of C,Mn and Al promotes the austenite stabilization during intercritical annealing,which causes the partitioning process with less time of the tested steel.