Si、Mg添加量对Al-Mg-Si合金的显微组织和Mg_(2)Si相形貌的影响  

Effects of Varying Si and Mg Levels on the Microstructural and Eutectic Mg_(2)Si Morphology in Al-Mg-Si Alloys

作　　者：唐玲[1] 夏鹏举[1] 李文虎[1] TANG Ling;XIA Pengju;LI Wenhu(School of Materials Science and Engineering,Shaanxi University of Technology,Hanzhong 723003,China)

机构地区：[1]陕西理工大学材料科学与工程学院,陕西汉中723003

出　　处：《有色金属工程》2022年第2期24-30,共7页Nonferrous Metals Engineering

基　　金：陕西省科技厅科研基金项目(2020JM-599)。

摘　　要：采用光学显微镜(OM)、扫描电子显微镜(SEM)等手段研究分析了Al-8.8Mg-9.2Si、Al-12.6Mg-7.4Si、Al-15.4Mg-9.8Si三种不同Mg_(2)Si含量的合金在金属型下的铸态凝固组织演化。结果表明,合金的凝固路径为L→L_(1)+Mg_(2)Si→L_(2)+Mg_(2)Si+(Al+Mg_(2)Si)_(二元共晶)→Mg_(2)Si+(Al+Mg_(2)Si)_(二元共晶)+(Al+Mg_(2)Si+Si)_(三元共晶),室温下的凝固组织为一定量的初生Mg_(2)Si相、二元共晶和三元共晶集群构成。随着Si含量和Mg含量的增加,初生Mg_(2)Si相的数量增加,其生长形态由八面体多边形向二次枝晶壁较为发达的树枝晶状转变,共晶Mg_(2)Si相的形态并没有明显的转变。通过对比Al-12.6Mg-7.4Si、Al-15.4Mg-9.8Si合金的凝固组织形貌,发现共晶晶胞的纵横比率累积值随着计算Mg_(2)Si含量的增加而下降。Solidification microstructure evolution of as-cast Al-8.8Mg-9.2Si,Al-12.6Mg-7.4Si and Al-15.4Mg-9.8Si with different calculated Mg_(2)Si content in the ferrous mold were studied by optical microscope(OM)and scanning electron microscope(SEM).The results show that the solidification path of the three alloys are L→L_(1)+Mg_(2)Si→L_(2)+Mg_(2)Si+(Al+Mg_(2)Si)_(binary eutectic)→Mg_(2)Si+(Al+Mg_(2)Si)_(binary eutectic)+(Al+Mg_(2)Si+Si)_(ternary eutectic).The solidification microstructure at room temperature is composed of a certain amount of primary Mg_(2)Si phase,binary eutectic and ternary eutectic clusters.With increasing Si content and Mg content,the number of primary Mg_(2)Si phase increases,its growth morphology changes from octahedral polygon to dendritic with more developed secondary dendritic walls,but the morphology of the eutectic Mg_(2)Si phase did not change significantly.The solidification microstructure morphology of Al-12.6Mg-7.4Si and Al-15.4Mg-9.8Si alloys was compared and it was found that the cumulative value of the aspect ratio of eutectic cells decreased with the increase of Mg_(2)Si content.

关 键 词：AL-MG-SI合金 计算Mg_(2)Si含量 初生相 纵横比率 

分 类 号：TG146[一般工业技术—材料科学与工程]