(郑州大学 材料工程学院， 郑州 450002)
摘 要: 研究了RE对Mg-8Zn-4Al-0.3Mn铸造镁合金显微组织的影响。 结果表明： Mg-8Zn-4Al-0.3Mn-xRE铸造镁合金的显微组织主要由α(Mg)基体、φ（Al2Mg5Zn2）相、τ(Mg32(Al, Zn)49)相和Mg3Al4Zn2RE相组成。随RE加入量的增加， 合金晶界上三元相的形态由半连续网状改变为颗粒状，三元相的分布逐渐变得弥散而均匀。 晶界上针状或棒状Mg3Al4Zn2RE相的量也随着RE加入量的增加而增加。 加入1.5%的RE可显著细化合金的铸态组织， 晶粒大小由120～130μm减小到40～50μm。合金的显微硬度值随着RE加入量的增加而增加。
关键字: Mg-8Zn-4Al-0.3Mn镁合金； RE； 显微组织
Mg-8Zn-4Al-0.3Mn magnesium alloys
（School of Materials Engineering, Zhengzhou University,
Zhengzhou 450002, China）
Abstract:The effects of RE on microstructure of Mg-8Zn-4Al-0.3Mn casting magnesium alloys were studied. The results show that casting microstructures of Mg-8Zn-4Al-0.3Mn magnesium alloys mainly contain α（Mg） matrix, eutectic α（Mg）, φ（Al2Mg5Zn2）phase and τ(Mg32(Al, Zn)49) phase. The morphology of ternary phases on the grain boundaries changes from quasi-continuous net to particle and the distribution of ternary phases gradually changes to be dispersive and homogeneous and the quantities of needle-shaped or rod-shaped Mg3Al4Zn2RE phase on the grain boundaries increase with the increases of RE addition. As-cast microstructures of Mg-8Zn-4Al-0.3Mn magnesium alloys can be refined by addition of 1.5% RE obviously. The size of grains decreases from 120-130μm to 40-50μm. The microhardness values of Mg-8Zn-4Al-0.3Mn magnesium alloys increase with the increases of RE addition.
Key words: Mg-8Zn-4Al-0.3Mn magnesium alloys; RE; microstr
