Al5TiB、RE对Mg-8Zn-4Al-0.3Mn合金显微组织和时效过程的影响  

Effect of Al5Ti and RE on Microstructure and Aging Process of Mg-8Zn-4Al-0.3Mn Alloy

作　　者：关绍康[1] 王迎新[1] 

机构地区：[1]郑州大学材料科学与工程学院,河南郑州450002

出　　处：《铸造技术》2004年第5期374-377,共4页Foundry Technology

摘　　要：研究Al5TiB、RE对Mg 8Zn 4Al 0 .3Mn铸造镁合金显微组织、时效过程的影响。结果表明 :加入Al5TiB的Mg 8Zn 4Al 0 .3Mn合金的显微组织主要由Mg相、 (Al2 Mg5Zn2 )相、τ(Mg3 2 (Al,Zn) 4 9)相组成。晶粒大小可由 12 0～ 13 0 μm减少到 3 0～ 40 μm。加入RE的Mg 8Zn 4Al 0 .3Mn xRE合金的显微组织主要由Mg相、 (Al2 Mg5Zn2 )相、τ(Mg3 2 (Al,Zn) 4 9)相和Mg3Al4Zn2RE相组成。晶粒大小由 12 0～ 13 0 μm减少到 40～ 5 0 μm。合金的显微硬度值随RE加入量的增加而增加。随着Ti元素在合金中含量的增加 ,合金的析出相形成激活能呈先增大后减小的变化规律 ,而含RE元素合金的析出相形成激活能则随RE元素加入量的增大而增大。Effect of Al5Ti and RE on Microstructure and Aging Process of Mg-8Zn-4Al-0.3Mn Alloy is studied. It is showed that microstructure of Mg-8Zn-4Al-0.3Mn is made up of Mg phase, (Al_2Mg_5Zn_2) phase and τ(Mg_(32)(Al,Zn)_(49))phase with addition of Al5TiB element. The Size of grain is reduced from 120～130 μm to 30～40 μm. The more content of Al5TiB, the more quantity ofα(Mg)phase,but the microstructure of alloy isn’t changed. Microstructure of Mg-8Zn-4Al-0.3Mn is made up of Mg phase, (Al_2Mg_5Zn_2) phase,τMg_(32)((Al,Zn)_(49)))phase and Mg3Al4Zn2RE phase with addition of RE element. Along with the increase of RE content, triple pointe is changed from original continuous net shape to grain shape to distrubte. The Size of grain is reduced from 120～130 μm to 40～50 μm. The more content of RE, the more microhardness of alloy.Aging process without modified Mg-8Zn-4Al-0.3Mn alloy is supersaturation liquid→tiny precipitating phase→growth of recrystallizing and softening phase→noncontinuous precipitating layer. With element of Ti and Re, the aging process is supersaturation liquid→tiny precipitating phase→growth of recrystallizing and softening phase. When Ti element increases, the precipitating phase changes greatly (from big to small). When RE element increases, so does the precipitiating phase.

关 键 词：Mg-8Zn-4AI-0.3Mn合金 AI5TiB 稀土 显微组织 时效过程 

分 类 号：TG115[金属学及工艺—物理冶金]