球墨铸铁的塑性变形及奥贝组织研究

Plastic Deformation and Austenite/Bainite Microstructure of Ductile Iron

利用Gleeble-1500热力学模拟机、光学和透射电子显微镜对球墨铸铁变形前后以及等温淬火处理后的组织进行了分析。结果表明，球铁热塑性变形最佳温度在750—800℃区间，此时流变应力接近950℃时的流变应力；变形后球铁为三层组织结构“球状石墨＋蠕虫状石墨＋流线型石墨”；在透射电镜下清楚地观察到不同形状的下贝氏体和上贝氏体形貌以及典型的隐“M”型马氏体形貌。

The microstructure of ductile iron before and after deformation and its austempering treatment was analyzed by Gleeble-1500 thermal mechanical simulator,OM and TEM. The results show that the optimum temperature of hot plastic deformation of ductile iron is in the range of 750 - 800 ℃, in which the stress is near the flow stress of 950 ℃, and the microstructure of the ductile iron after deformation consists of three layers, spheroidal graphite, vermiculate graphite and streamline shape graphite. Different shape of lower bainite, upper bainite and typical implicit＂ M＂ model martensite can be found clearly by TEM.