镍对Fe-Cu-Ni钢中富铜相析出强化的影响  

Effect of Nickel on Strengthening of Fe-Cu-Ni Steel by Precipitation of Copper-rich Phase

作　　者：李彤 李嘉宝 刘文庆[1] LI Tong;LI Jiabao;LIU Wenqing(Institute of Materials, Shanghai University, Shanghai 200444, China)

机构地区：[1]上海大学材料研究所,上海200444

出　　处：《上海金属》2020年第2期1-7,共7页Shanghai Metals

基　　金：国家重点研发计划(No.2017YFB0703002);东北大学轧制技术及连轧自动化国家重点实验室(2016002)。

摘　　要：对超低碳Fe-Cu和Fe-Cu-Ni钢进行了900℃×2 h水冷的固溶处理,随后于450℃分别时效0.25、2、8和32 h。检测了热处理后钢的显微硬度和拉伸性能,以研究富铜相的析出强化效果。采用透射电镜(TEM)和原子探针层析技术(APT)研究了钢中富铜相的析出特征。结果显示:两种钢达到硬度峰值的时效时间相近;由于镍的固溶强化和细晶强化作用,时效相同时间的Fe-Cu-Ni钢的硬度高于Fe-Cu钢;经时效处理的Fe-Cu钢的最高硬度和抗拉强度分别为230 HV0.1和560 MPa,而Fe-Cu-Ni钢的则相应为264 HV0.1和861 MPa,均高于未经时效的钢的硬度和抗拉强度。APT分析表明:时效0.25和2 h的Fe-Cu-Ni钢中镍阻碍了富铜相的形核,时效32 h的Fe-Cu-Ni钢中镍在富铜相与基体界面间富集,形成核壳结构,其对富铜相的长大和结构影响不大。Ultra-low-carbon Fe-Cu and Fe-Cu-Ni steels were solution treated at 900℃for 2 h,cooled in water,then aged at 450℃for 0.25 h,2 h,8 h and 32 h,respectively.After this,micro-hardness and tensile properties were tested to discover the effect of precipitation of copper-rich phase on the strengthening of the two steels.Characteristics of copper-rich phase precipitation in the steels were investigated by using transmission electron microscope and atom probe tomography.The results showed that the duration of aging time was similar to the two steels to get the maximum hardness,after aging for the same time hardness of the Fe-Cu-Ni steel was higher than one of the Fe-Cu steel due to solution strengthening and grain refinement strengthening induced by nickel.After aging,the maximum hardness and tensile strength of the Fe-Cu steel were 230 HV0.1 and 560 MPa,but those of the Fe-Cu-Ni steel were correspondingly 264 HV0.1 and 861 MPa,which were higher than those of the steels not aged.From atom probe tomography testing it was seen that the nucleation of copper-rich phase in the Fe-Cu-Ni steel aged for 0.25 h and 2 h was hindered by nickel,and nickel concentrated at interface between the copper-rich phase and the matrix in the Fe-Cu-Ni steel aged for 32 h,to form a core-shell structure,which had no significant effect on growth and structure of the Cu-rich phase.

关 键 词：时效 析出强化 富铜相 镍 原子探针层析技术 

分 类 号：TG1[金属学及工艺—金属学]