低碳钢过冷奥氏体形变过程组织演变机制  

Mechanisms of Microstructure Evolution during Deformation of Undercooled Austenite in a Low Carbon Steel

作　　者：齐俊杰[1] 杨王玥[1] 孙祖庆[2] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]新金属材料国家重点实验室,北京100083

出　　处：《北京科技大学学报》2002年第2期97-102,共6页Journal of University of Science and Technology Beijing

基　　金：国家"973"资助项目(No.G1998061506)

摘　　要：低碳钢过冷奥氏体形变过程将发生形变强化相变及铁素体的动态再结晶，导致晶粒 超细化．与未形变的过冷奥氏体等温转变相比，形变极大地促进了奥氏体向铁素体的转变，使 铁素体形核率急剧升高，铁素体晶粒尺寸显著降低．形变强化相变是一以形核为主的过程．在 形变后期，当形变强化相变铁素体转变基本完成后，将发生铁素体的动态回复和动态再结晶． 比较不同应变速率对组织演变影响的结果表明，应变速率较低条件下，易形成铁素体与第２组 织层状分布的条带特征；应变速率较高时，组织的条带特征不显著．Two mechanisms-deformation enhanced transformation and dynamic recrystallization of ferrite are involved during deformation of undercooled austenite in a low carbon steel, leading to effective fer- rite grain refinement. In comparison with isothermal transformation, deformation significantly accelerates aus- tenite to ferrite transformation, leading to a very high nucleation rate. Deformation enhanced transformation is a nucleation dominant process. The results of EBSD and TEM indicate that ferrite dynamic recrystallization also plays an important role on grain refinement as well as deformation enhanced transformation. The misorien- tation of sub-grain boundaries is assumed to increase by further straining, accompanied by grain rotation, finally leading to the recrystallized small ferrite grains. Study on the effect of strain rate on microstructure homogene- ity indicates that microstructure tends to be distributed in a laminar manner at lower strain rate.

关 键 词：低碳钢 过冷奥氏体 形变过程 组织演变机制 晶粒细化 

分 类 号：TG142.31[一般工业技术—材料科学与工程]