脉冲磁场孕育处理下A356铝合金凝固组织的演变规律  

Evolution of Solidification Microstructure of A356 Aluminum Alloy Treated by Pulse Magnetic Field

作　　者：宋志起 赵旭东 王军[1] 胡朝晟 刘永珍[1] 麻永林[1] SONG Zhiqi;ZHAO Xudong;WANG Jun;HU Chaosheng;LIU Yongzhen;MA Yonglin(Institute of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,Inner Mongolia,China;Baotou Huizhong Aluminum Alloy Forging Co.,Ltd.,Baotou 014030,Inner Mongolia,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 [2]包头汇众铝合金锻造有限公司,内蒙古包头014030

出　　处：《材料导报》2024年第13期192-198,共7页Materials Reports

基　　金：内蒙古自治区科技计划项目(2021GG0096)。

摘　　要：基于自行设计的磁场晶粒细化装置,研究在不同频率的脉冲磁场孕育处理下A356铝合金凝固组织的演变规律,利用蔡司显微镜(OM)、场发射扫描电镜(FESEM)、X射线衍射仪(XRD)、差示扫描量热仪(DSC)等测试方法对A356铝合金的凝固组织进行分析。结果表明:脉冲磁场孕育处理能降低形核激活能与临界形核半径,影响液相线以上原子团的演变规律,使得原子团的尺寸减小,数目增加,并在更小的临界尺度上形成大量稳定晶核,从而导致A356铝合金凝固组织中初生α-Al相和共晶Si相显著细化;其中频率为30 Hz的脉冲磁场细化效果最佳,与未处理相比,试样初生α-Al晶粒平均尺寸下降39%,共晶Si平均尺寸下降60%。同时α-Al晶粒磁各向异性产生的磁各向异性能与磁转矩导致α-Al晶粒发生旋转,使得晶粒沿(200)面择优生长。Based on the self-designed magnetic field grain refinement device,the evolution law of solidification microstructure of A356 aluminum alloy under different frequency of pulsed magnetic field incubation treatment was studied.The solidification structure of A356 aluminum alloy was analyzed by Zeiss microscope(OM),field emission scanning electron microscope(FESEM),X-ray diffractometry(XRD)and differential scanning calorimetry(DSC).The results showed that:under pulsed magnetic field inoculation can reduce nucleation activation energy and the critical nucleation radius,affects the evolution law of the groups above liquidus,makes the size of the groups of watoms is reduced,the number increased,and the smaller the critical dimension on a large number of stable crystal nucleus formation,so as to make the primaryα-Al in A356 aluminum alloy solidification organization and eutectic silicon phase significant refinement,compared with the untreated samples,the average size of primaryα-Al grains decreases by 39%,and the average size of eutectic silicon decreases by 60%.At the same time,due to the magnetic anisotropy ofα-Al grains,the magnetic anisotropy energy and magnetic torque lead to the rotation ofα-Al grains,so that the grains grow along the(200)plane preferentially.

关 键 词：A356铝合金 脉冲磁场 凝固组织 频率 初生α-Al相 

分 类 号：TF821[冶金工程—有色金属冶金]