工程科学学报，第41卷，第7期：882-888.2019年7月 Chinese Journal of Engineering,Vol.41,No.7:882-888,July 2019 DOI:10.13374/j.issn2095-9389.2019.07.006;http://journals.ustb.edu.cn Nb在高铝铁素体钢中的固溶析出行为 刘鹏程”，徐翔宇)，刘倩男)，李建赭2)，刘丹)，延泽鹏”，孙明煜)，王学 敏1)四 1)北京科技大学钢铁共性技术协同创新中心，北京1000832)北京科技大学材料科学与工程学院，北京100083 区通信作者，E-mail:wxm@mater..ustb.edu.cm 摘要采用电解相分析方法，结合X射线衍射分析和电感耦合等离子体原子发射光谱仪(ICP)、扫描电镜(SEM)、透射电镜 (TEM)等对高铝铁素体基体中的析出相颗粒粉末和电解液进行定性定量分析.试验结果表明，试验钢中固态析出相主要为 NC以及少量的ALO3和AN夹杂.通过扫描电镜观察不同再加热温度下NbC分布状态，发现随着固溶温度的升高，铸态组 织中存在的NbC析出逐渐回溶，数量随之减少且发生明显的粗化行为.当温度升高到1100℃，大部分NbC已经回溶到高温铁 素体基体中.在利用Thermo--Calc热力学计算软件分析Nb及其碳化物的热力学性质基础上，计算得到Al与Nb的相互作用 系数，表明A1能够降低Nb在铁索体基体中的活度，提高其在基体中的固溶度，进一步得到了NC在高铝铁索体钢中的固溶 度积公式，发展了高温铁素体中的Nb微合金化理论，为进一步的应用提供了理论基础. 关键词高铝铁素体钢；碳化铌；相互作用系数；固溶度积；物理化学相分析 分类号TG142.1 Solid solution and precipitation behavior of Nb in Al-bearing ferritic steels LIU Peng-cheng,XU Xiang-yu,LIU Qian-nan,LI Jian-zhe,LIU Dan,YAN Ze-peng,SUN Ming-yu,WANG Xue- min)图 1)Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,China 2)School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China Corresponding author,E-mail:wxm@mater.ustb.edu.cn ABSTRACT With the rapid development of the global economy,problems in energy production and environmental protection are be- coming severe.To reduce fuel consumption and CO emissions,it is essential to reduce the weight of automobiles and other huge con- struction structures.Recently,a number of studies have been conducted on the use of low-density steels for automobile applications by incorporating aluminum in steel.The light elements can increase the lattice constant of steel while reducing the density of steel to a- chieve a lower atomic weight.Aluminum as a light element replaces the iron atoms in the unit cell,increasing the volume while reduc- ing the weight,thereby reducing the density of steels.In this regard,ferritic Fe-8%Al steels indicated a 10%reduction in density compared with the conventional steels.To clarify the solid solution and precipitation behavior of Nb in Al-bearing ferritic steels,heat treatment tests were carried out under a series of temperature.The precipitates of NbC and the dissolved Nb solute in ferrite matrix with high Al content were studied using electrolytic dissolution technique,X-ray diffraction technique,and inductively coupled plasma-atom- ic emission spectrometry (ICP-AES).Scanning electron microscopy (SEM)and transmission electron microscopy (TEM)were also applied.The experimental results show that the precipitates are NbC and also some AlO and AIN inclusions.It is also found that with increase in the solution temperatures,the NbC in the as-cast samples becomes fewer and the coarsening behavior occurs.Moreover, when the temperature was over 1100C,almost all the precipitates were dissolved.Furthermore,using Thermo-Cale software,the ther- modynamic properties of Nb and relevant compounds were studied,and the interaction coefficient between Al an Nb was calculated. 收稿日期：2019-01-12工程科学学报,第 41 卷,第 7 期:882鄄鄄888,2019 年 7 月 Chinese Journal of Engineering, Vol. 41, No. 7: 882鄄鄄888, July 2019 DOI: 10. 13374 / j. issn2095鄄鄄9389. 2019. 07. 006; http: / / journals. ustb. edu. cn Nb 在高铝铁素体钢中的固溶析出行为 刘鹏程1) , 徐翔宇1) , 刘倩男1) , 李建赭2) , 刘 丹1) , 延泽鹏1) , 孙明煜1) , 王学 敏1) 苣 1) 北京科技大学钢铁共性技术协同创新中心, 北京 100083 2) 北京科技大学材料科学与工程学院, 北京 100083 苣通信作者, E鄄mail: wxm@ mater. ustb. edu. cn 摘 要 采用电解相分析方法,结合 X 射线衍射分析和电感耦合等离子体原子发射光谱仪(ICP)、扫描电镜(SEM)、透射电镜 (TEM)等对高铝铁素体基体中的析出相颗粒粉末和电解液进行定性定量分析. 试验结果表明,试验钢中固态析出相主要为 NbC 以及少量的 Al 2O3 和 AlN 夹杂. 通过扫描电镜观察不同再加热温度下 NbC 分布状态,发现随着固溶温度的升高,铸态组 织中存在的 NbC 析出逐渐回溶,数量随之减少且发生明显的粗化行为. 当温度升高到 1100 益 ,大部分 NbC 已经回溶到高温铁 素体基体中. 在利用 Thermo鄄鄄Calc 热力学计算软件分析 Nb 及其碳化物的热力学性质基础上,计算得到 Al 与 Nb 的相互作用 系数,表明 Al 能够降低 Nb 在铁素体基体中的活度,提高其在基体中的固溶度,进一步得到了 NbC 在高铝铁素体钢中的固溶 度积公式,发展了高温铁素体中的 Nb 微合金化理论,为进一步的应用提供了理论基础. 关键词 高铝铁素体钢; 碳化铌; 相互作用系数; 固溶度积; 物理化学相分析 分类号 TG142郾 1 收稿日期: 2019鄄鄄01鄄鄄12 Solid solution and precipitation behavior of Nb in Al鄄bearing ferritic steels LIU Peng鄄cheng 1) , XU Xiang鄄yu 1) , LIU Qian鄄nan 1) , LI Jian鄄zhe 2) , LIU Dan 1) , YAN Ze鄄peng 1) , SUN Ming鄄yu 1) , WANG Xue鄄 min 1) 苣 1) Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China 2) School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China 苣 Corresponding author, E鄄mail: wxm@ mater. ustb. edu. cn ABSTRACT With the rapid development of the global economy, problems in energy production and environmental protection are be鄄 coming severe. To reduce fuel consumption and CO2 emissions, it is essential to reduce the weight of automobiles and other huge con鄄 struction structures. Recently, a number of studies have been conducted on the use of low鄄density steels for automobile applications by incorporating aluminum in steel. The light elements can increase the lattice constant of steel while reducing the density of steel to a鄄 chieve a lower atomic weight. Aluminum as a light element replaces the iron atoms in the unit cell, increasing the volume while reduc鄄 ing the weight, thereby reducing the density of steels. In this regard, ferritic Fe鄄鄄8 % Al steels indicated a 10% reduction in density compared with the conventional steels. To clarify the solid solution and precipitation behavior of Nb in Al鄄bearing ferritic steels, heat treatment tests were carried out under a series of temperature. The precipitates of NbC and the dissolved Nb solute in ferrite matrix with high Al content were studied using electrolytic dissolution technique, X鄄ray diffraction technique, and inductively coupled plasma鄄atom鄄 ic emission spectrometry (ICP鄄鄄AES). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were also applied. The experimental results show that the precipitates are NbC and also some Al 2O3 and AlN inclusions. It is also found that with increase in the solution temperatures, the NbC in the as鄄cast samples becomes fewer and the coarsening behavior occurs. Moreover, when the temperature was over 1100 益 , almost all the precipitates were dissolved. Furthermore, using Thermo鄄Calc software, the ther鄄 modynamic properties of Nb and relevant compounds were studied, and the interaction coefficient between Al an Nb was calculated