低合金钢中贝氏体组织回复与再结晶的原位追踪研究  

In situ tracing investigation of recovery and recrystallization of bainite in a low alloy steel

作　　者：孙超[1] 杨善武[1] 张瑞[1] 王宪[1] 郭晖[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《材料热处理学报》2013年第12期85-90,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(50671016);国家重点基础研究发展计划(2010CB630801)

摘　　要：对一种低合金钢中的贝氏体组织在550、600和650℃等温过程中的组织演化进行了原位追踪研究。结果表明:贝氏体在A1温度以下通过回复与再结晶方式向多边形铁素体演化,随着等温温度升高,不但整体演化进程明显加快而且演化行为也发生变化。在550℃,新的再结晶晶粒形核于原奥氏体晶界并在长大过程中吞食贝氏体铁素体和粒状贝氏体;当温度升高至600℃以上时,一部分贝氏体铁素体转变为粒状贝氏体,继而转变为多边形铁素体;在较高的650℃,预先存在的粒状贝氏体能够发生明显的扩张并吞食贝氏体铁素体。贝氏体的重加热演化过程与形变金属的退火过程有明显区别,其主要原因在于贝氏体中来自于贝氏体相变的高密度位错具有独特的分布方式。In situ tracing investigation was carried out to investigate the evolution of bainite in a low alloy steel during isothermal holding at 550, 600 and 650 ℃. The results show that bainite evolves into polygonal ferrite via recovery and recrystallization below A1 temperature, and the evolution process is not only accelerated but also the evolution behavior is changed as the holding temperature is elevated. At 550 ℃ , new recrystallized ferrite grains is found to nucleate at boundaries of prior austenite grains and to consume bainitic ferrite and granular bainite. At 600 ℃ , some packets of bainitic ferrite are found to evolve into granular bainite and then the granular bainite evolves into polygonal ferrite. At 650 ℃ , pre-existing granular bainite is found to expand markedly and to consume bainitic ferrite. It is found that the evolution of bainite during reheating is different from that in annealing process of deformed metals because the distribution of dense dislocations coming from bainitic transformation is different from that in the deformed metals.

关 键 词：贝氏体 等温处理 原位追踪 回复 再结晶 

分 类 号：TG142.1[一般工业技术—材料科学与工程]