低合金超级贝氏体钢组织形态的研究.pdf

第22卷第5期
材料科学与工艺
Vol 22 No
2014年10月
MATERIALS SCIENCE &TECHNOLOGY
Oct.2014
低合金超级贝氏体钢组织形态的研究
吴化,张翠翠,梁言,刘云旭
(长春工业大学先进结构材料教育部重点实验室,长春130012
摘要:针对贝氏体研究中的超级贝氏体纽织,设计了试验用钢70MnSi2CrMo,经低温等温处理,获得贝氏体铁素体+残
余奥氏体的组织,利用X射线衍射XRD、扫描电子显微镜SFM、透射电子显微镜TFM等仪器对其进行相組成和形态的
检测分析.结果表明:在马氏体转变开始温度Ms点稍上的中低温区等温处理,贝氏体铁素体沿γ相晶界转变,无化物
析出;相转变排碳导致成分起伏,w/y交界处过冷奥氏体稳定性增加,难以转交成马氏体;氏体铁素体的转变特征
过饱和的碳浓度、高密度位错、以及納米尺寸相界面和亚结构等,影响着超級贝氏体钢的力学性能
关键词:超級贝氏体;贝氏体铁素体;残余奥氏体;组织;转变温度
中图分类号:TG113.12
文献标志码:A文章编号:1005-0299(2014)05-0102-06
Study on microstructure of the low-alloying super bainitic steel
WU Hua AHANG Cuicui. LANG Yan. LLU Yunxu
(Key Iaboratory of Advanced Structural Materials, Ministry of Education
Changchun University of Technology. Changchun 130012. China
Abstract The experimental steel 70 Mnsi2crmo was designed for the purpose to obtain bainite ferrite and
retained austenite microstructure by isothermal treatment al lower temperature. The microstructure and phase
composition of the treated steel were investigated by XRD, SEM and TEM. The results showed that the phase
transformation of the bainite ferrite generated along the grain boundary of the phase y when the employed
temperature was over the martensite start temperature(Ms), with no carbide precipitation. Simultaneously, the
inhomogeneous composition distribution in the a phase was obtained for the discharging of carbon atoms
therefore, the martensite was difficult to generate for the increasing stability of the undercooling austenite at the
edge of a and y phases. Generally, the transformation behavior of bainite ferrite, oversaturated carbon
concentration high dislocation density, and the nanoscale phase interface and substructure generated between
bainite ferrite and retained austenite, are the factors affecting the mechanical properties of super bainitic steel
Keywords super bainite; bainite ferrite; retained austenite; microstructure; transformation temperature
英国剑桥大学 Bhadeshia工作组在含硅低合论是强度还是韧性,均有显著提高?.为有别于
金钢中发现的新型贝氏体组织因具有较高的综其它贝氏体钢种,将具有上述显微组织特征的
合力学性能,而受到人们的关注.该类钢经钢称为超高强度贝氏体钢( Ultra high strength
奥氏体化后在低温下长时间等温(数小时~数十 Bainitic Steels)或超级贝氏体钢( super bainitic
天)可获得由针状铁素体+薄膜状残余奥氏体构Siel),其组织称为超强低温贝氏体(Very
成的组织,其强度可达到2500MPa,切性大于 strong low temperature bainite)或超级贝氏体(su
30~40J.与传统贝氏体的力学性能相比较,无 per bainitic).由于超级贝氏体与传统贝氏体在
组成相和力学性能上存在着较大差別,研究工
收稿日期:2013-(06-18.
作结合已有贝氏体的研究成果对超级贝氏体的
基金项目:国家自然科学基金资助项日(51171030)
形成温度、组成相及其力学性能之间的关系进
作者简介:吴化(1957-),男,博十,教授
通信作者:吴化,F-mail: wuhua57@163.co0m
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