摘要
近年来,贝氏体钢轨由于具有优良的强韧性、焊接性及耐磨损性能、抗疲劳性能,得到广泛关注。贝氏体钢轨中通常包含贝氏体铁素体、马氏体和残余奥氏体复相组织。而贝氏体铁素体和马氏体都是体心立方结构,如何区分并定量表征贝氏体铁素体和马氏体的含量是目前复相钢面临的一个难题。本实验采用彩色金相法、电子背散射衍射(EBSD)法、纳米压痕法及膨胀仪法(并结合XRD分析)对重载铁路用贝氏体钢轨显微组织进行定量表征。结果表明:四种方法测定的贝氏体铁素体、马氏体比例基本一致。其中,贝氏体铁素体的比例(以下均为体积分数)为47.3%~53.5%,马氏体的比例为40.3%~46.5%,残余奥氏体的含量为6.2%(经XRD测定)。彩色金相法最为方便经济;而EBSD法和纳米压痕法可以区分更为精细的组织类型。
Recently,bainitic rail steel attracts a lot of attention because of its excellent combination of strength and toughness,good weldability and high resistance of wear and fatigue.In general,the multiphase microstructure of bainitic rail steel contains bainitic ferrite,martensite and retained austenite.Bainitic ferrite and martensite have similar body-centered cubic crystal structure,so how to distinguish bainitic ferrite and martensite and quantitatively characterize the microstructure of bainitic rail steel becomes a difficult problem.In this paper,four kinds of experimental metallographic methods,namely,color metallography,electron backscatter diffraction(EBSD),nano indentation and dilatometer methods accompanied with XRD analysis,were employed to distinguish the martensite and bainitic ferrite and to measure their fractions in bainitic rail steel.The results show that the fractions of bainitic ferrite and martensite analyzed by the four methods are similar,with 47.3vol%—53.5vol%of bainitic ferrite,40.3vol%—46.5vol%of martensite and 6.2vol%of retained austenite(obtained by XRD),respectively.Among the four methods,color metallography is the most convenient and economical method,while EBSD and nano indentation could distinguish more refined microstructural details in multiphase.
作者
桂晓露
王琨
苏浩
高古辉
白秉哲
GUI Xiaolu;WANG Kun;SU Hao;GAO Guhui;BAI Bingzhe(School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong University,Beijing 100044,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第22期22136-22141,共6页
Materials Reports
基金
国家重点研发计划(2017YFB0304501)。
关键词
贝氏体
马氏体
钢轨
复相组织
定量表征
bainite
martensite
rail
multiphase microstructure
quantitative characterization
