中文摘要：

采用光学金相和扫描电镜技术相结合的原位观察方法研究了一种低碳贝氏体钢在600℃等温过程中的组织演变规律。结果表明,在等温过程中低碳贝氏体钢中的组织是以类似于变形金属的回复和再结晶的方式向平衡组织转变,最终的转变产物为多边形铁素体。回复阶段在微观上主要表现为贝氏体板条内的位错重新分布形成胞状亚晶。在整个等温过程中,原奥氏体晶界是比较稳定的,在铁素体长大时有可能被穿越。而再结晶后形成的铁素体组织是以一种＂包晶＂的方式逐渐吞噬其他非平衡组织而长大。

英文摘要：

In-situ observation by optical and scanning electron microscopy was carried out to track the evolution when a low carbon bainite steel were isothermally held at 600 ℃.The results show that bainite in the steel can finally evolve into polygonal ferrite by the way of recovery and recrystallization,which is similar to deformed metals.At the stage of recovery,redistribution of dislocations inside bainite laths results in formation of cellular subgrain.The prior austenite grain boundary is a relatively stable structure during isothermal holding,which can be passed through when ferrite grows up.In addition,ferrite produced during recrystallization,grows up by a ＂peritectic＂ way to swallow up other non-equilibrium microstructure.