微米_亚微米双峰尺度奥氏体组织形成机制.docx

第 50 卷第 3 期Vol.50No.32014 年 3 月第 269-274 页ACTA METALLURGICA SINICAMar. 2014pp.269-274微米/亚微米双峰尺度奥氏体组织形成机制*武会宾 1)武凤娟 1)杨善武 2)唐 荻 1)1) 北京科技大学高效轧制国家工程研究中心, 北京 1000832) 北京科技大学材料科学与工程学院, 北京 100083摘 要 通过冷轧变形结合变形后在 820~870 ℃退火, 在 316L 奥氏体不锈钢中实现了微米(3~5 μm 为主)和亚微米(300~ 500 nm 为主)双峰晶粒尺度分布. 在奥氏体冷变形过程中, 形变孪生与应变诱导马氏体相变都集中发生于大变形阶段, 据此 推断奥氏体形变孪生是产生应变诱导马氏体的微观机制. 在 820~870 ℃范围内退火时, 样品的硬度和晶粒尺寸分布几乎 保持恒定. 通过对退火过程中变形奥氏体和应变诱导马氏体演化驱动力的比较分析, 推断奥氏体双峰尺度晶粒尺寸分布 的来源是: 微米尺度晶粒来自冷变形时未转变的变形奥氏体的再结晶, 而亚微米尺度晶粒主要由应变诱导马氏体逆转变 而产生.关键词 微米/亚微米, 双峰晶粒尺寸分布, 原位拉伸, 形成机制中图法分类号 TG142.7文献标识码 A 文章编号 0412-1961(2014)03-0269-06THE FORMATION MECHANISM OF AUSTENITE STRUCTURE WITH MICRO/SUB-MICROMETER BIMODAL GRAIN SIZE DISTRIBUTIONWU Huibin 1), WU Fengjuan 1), YANG Shanwu 2), TANG Di 1)1) National Engineering Research Center for Advanced Rolling Technology, University of Science and Technology Beijing, Beijing 1000832) School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 Correspondent: WU Huibin, associate professor, Tmailto:Wuhb@ustb.edu.cnel: (010 E-mail: Wmailto:uhb@ustb.edu.cnuhb@ustb.edu.cn Supported by National Science and Technology Major Project of the Ministry of Science and Tech-nology of China (No.2011ZX05016-004)Manuscript received 2013-09-09, in revised form 2013-12-13ABSTRACT Nano-crystalline (100 nm) and ultrafine grained (100~500 nm) materials have high strength and toughness, but its work hardening ability and uniform elongation decreased relative to the coarse grained material. Through the deformation, phase transformation and recrystallisation combination mode of development of bimodal grain size distribution of ferrite, bainite steel, the elongation rate is greatly improved. These studies are generally in order to improve the mechanical properties of material through change microstructure, but lack of study for the bi- modal grain size distribution formation mechanism. This research work by cold rolling with annealing at 8