低碳钢中贝氏体组织在A_1温度以下重加热过程中的演化与热稳定性  

Evolution and thermal stability of bainite in a low-carbon steel during reheating below A_1 temperature

作　　者：孙超[1] 杨善武[1] 王宪[1] 张瑞[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：《北京科技大学学报》2013年第7期875-881,共7页Journal of University of Science and Technology Beijing

摘　　要：通过原位追踪金相观察、维氏硬度测试、透射电子显微术、电子背散射衍射等实验手段研究了低碳钢中贝氏体组织在550～675℃范围内重加热过程中的演化与热稳定性.实验结果表明:贝氏体组织通过回复与再结晶方式演化为多边形铁素体,在该过程中粒状贝氏体首先演化为多边形铁素体,然后多边形铁素体再吞噬贝氏体铁素体,贝氏体铁素体表现出了高于粒状贝氏体的热稳定性;在回复过程中,贝氏体铁素体中相邻铁素体板条之间的小角度晶界部分撤除,铁素体板条发生倾转与合并;贝氏体组织在重加热过程中的演化存在一个稳定阶段,处于回复与再结晶之间,其持续时间随温度的降低而显著延长.In-situ tracing metallographic observation, Vickers hardness test, transmission electron microscopy and electron back-scattered diffraction were carried out to investigate the evolution and thermal stability of bainite in a low- carbon steel during reheating in a temperature range of 550 to 675℃. Experimental results show that the bainite evolves into polygonal ferrite through the way of recovery and recrystallization. In this process the granular bainite changes into polygonal ferrite firstly and then the polygonal ferrite consumes bainitic ferrite, so the bainitic ferrite exhibits a higher thermal stability than the granular bainite. During recovery, low degree boundaries between adjoining ferrite laths are partially removed, and the ferrite laths are tilted and merged. There is an evolutionary stable stage between recovery and recrystallization during reheating of bainite, and the duration of the stable stage is significantly prolonged with the drop of temperature.

关 键 词：低碳钢 贝氏体 热处理 演化 热稳定性 

分 类 号：TG142.1[一般工业技术—材料科学与工程]