Al-Ce合金对铝脱氧钛微合金钢中夹杂物的影响  

Effect of Al-Ce alloy on inclusions in Al deoxidization titanium microalloyed steel

作　　者：何飞虎 彭军[1] 张芳[1] 常宏涛[1] HE Fei-hu;PENG Jun;ZHANG Fang;CHANG Hong-tao(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,Nei Mongol,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010

出　　处：《钢铁》2023年第3期61-72,共12页Iron and Steel

基　　金：国家自然科学基金资助项目(51874186,51864041);内蒙古自治区自然科学基金资助项目(2022MS05017)。

摘　　要：为了研究不同的Al-Ce合金对钛微合金钢中含铈及含钛夹杂物的影响,通过SEM、EDS及OTS夹杂物全自动分析系统对钢中夹杂物的尺寸、数量、形貌及种类进行分析,采用FactSage 8.1热力学软件中的Equilib和Phase Diagram模块计算了不同温度下钢中夹杂物的析出情况。热力学计算结果表明,CeAlO_(3)主要在钢液中生成,Ce_(2)S_(3)和Ce_(2)O_(2)S则在钢液凝固的过程中析出。当铈质量分数为0.005%时,随着硫质量分数从0.000 8%增加至0.003 3%,稀土夹杂物类型由CeAlO_(3)、Ce_(2)S_(3)、Ce_(2)O_(2)S逐渐变为单一的Ce_(2)S_(3)。试验结果表明,在钢中依次加入3种不同Al-Ce合金(w(Ce)∶w(Al)依次为4.5∶1、8.5∶1和11.5∶1)时,钢中硫含量逐渐降低,典型含铈夹杂物依次为Ce_(2)S_(3)、Ce-Al-O-S和Ce_(2)O_(2)S-CeAlO_(3),形貌以椭球形和球形为主,稀土夹杂物平均尺寸从3μm增至5.5μm,加稀土合金的钢中Al2O_(3)和Ti(C, N)的尺寸相比未加稀土合金的钢均有所减少。根据二维错配度模型以及Ce-Al-O-S-Ti(C, N)夹杂物的面扫描结果,验证了在Ce-Al-O-S夹杂与TiN之间存在着CeN过渡的可能性。在采用w(Ce)∶w(Al)为11.5∶1的合金冶炼的钢中出现了CeAlO_(3)在Ce_(2)O_(2)S表面呈枝晶状析出的现象,利用边-边匹配模型证明了Ce_(2)O_(2)S可以成为CeAlO_(3)的形核核心,两者之间存在着4种可能的位向关系。钢中单独的Ti(C, N)长大方式为连续长大和二维晶核,当Ti(C, N)在不同稀土夹杂表面经过一定时间的形核及长大后,其最终生长特点均是以稀土夹杂物为异质形核核心,沿着其表面向各个方向呈立方结构生长。To investigate the effects of different Al-Ce alloys on cerium-containing and titanium-containing inclusions in titanium microalloyed steel,the size,quantity,morphology,and type of inclusions in steel were analyzed using a scanning electron microscope,energy dispersive spectroscope,and OTS inclusion automatic analysis system.The Equilib and Phase Diagram modules in FactSage 8.1thermodynamic software were used to calculate the precipitation of inclusions in steel at different temperatures.The thermodynamic calculation results show that CeAlO_(3)is mainly formed in molten steel,while Ce_(2)S_(3)and Ce_(2)O_(2)S are precipitated during the solidification of molten steel.When the mass percent of cerium is 0.005%,with the mass percent of sulfur increasing from 0.0008%to 0.0033%,the type of rare earth inclusions will gradually change from CeAlO_(3),Ce_(2)S_(3),and Ce_(2)O_(2)S to single Ce_(2)S_(3).The experi-mental results show that when Al-Ce alloys(w(Ce)∶w(Al)=4.5∶1,8.5∶1,and 11.5∶1)are added to the steel successively,the content of sulfur will gradually decrease,the typical cerium-containing inclusions in steel are Ce_(2)S_(3),Ce-Al-O-S and Ce_(2)O_(2)S-CeAlO_(3),the morphology is mainly ellipsoidal and spherical,and the average size of rare-earth inclusions increases from 3μm to 5.5μm,the size of Al2O_(3)and Ti(C,N)in steel with rare earth alloys is reduced compared with the steel without rare earth alloys.The possibility of CeN transition between Ce-Al-O-S inclusions and TiN is verified based on the two-dimensional mismatch degree model and the surface scanning results of Ce-Al-O-S-Ti(C,N)inclusions.In the steel smelted with the alloy of w(Ce)∶w(Al)=11.5∶1,CeAlO_(3)precip-itates in the form of dendrites on the surface of Ce_(2)O_(2)S.The edge-to-edge matching model proves that Ce_(2)O_(2)S can become the nucleation core of CeAlO_(3),and there are four possible orientation relationships between Ce_(2)O_(2)S and CeAlO_(3).Individual Ti(C,N)in steel has two growth models,continuous growth and two-dimen

关 键 词：热力学计算 边-边匹配模型 连续长大 二维晶核 异质形核 

分 类 号：TG142.1[一般工业技术—材料科学与工程]