【摘要】 采用高温激光共聚焦显微镜(LSCM)对一种先进贝氏体钢的奥氏体晶粒长大动态过程进行了原位观察研究。结果观察到奥氏体晶粒长大的3种方式,分别为奥氏体晶界的迁移和扩张、多个晶粒合并成一个大晶粒以及周围晶粒通过分割和吞并中间晶粒长大。原位观察还发现,当奥氏体化温度高于1100℃时,奥氏体晶粒会发生粗化;而低于1000℃时,奥氏体晶粒无明显变化。此外,得到了描述奥氏体晶粒尺寸随保温时间变化规律的Beck方程,讨论了奥氏体晶粒尺寸对贝氏体转变后的组织形貌的影响。LSCM原位观察方法为奥氏体晶粒长大动态过程的观察和研究提供了新的方法。更多还原

【Abstract】 In situ observation of dynamic process of austenite grain growth in an advanced bainite steel was carried out on high temperature laser scanning confocal microscope(LSCM).Three kinds of grain growth behavior are directly observed,i.e.expansion and migration of austenite grain,combination of some small grains as well as segmentation and merger of grains.The results indicate that the critical temperature for austenite grain coarsening is 1100 ℃.In addition,Beck equation indicating the relationship between austenite grain size and austenizing temperature for tested steel is obtained.Finally,the effect of austenite grain size on bainite morphology was discussed.This is a new method for analysis of dynamic evolution of annealing twins during austenization.更多还原