稀土Nd对Al-6.1Zn-2.3Mg-1.7Cu-0.15Zr铝合金铸造组织及性能的影响  

Rare Earth Nd on Casting Microstructure and Properties of Al-6.1Zn-2.3Mg-1.7Cu-0.15Zr Aluminum Alloy

作　　者：郝建鹏 闫亮明[1,2] 柳建国 Hao Jianpeng;Yan Liangming;Liu Jianguo(School of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China;Inner Mongolia Key Laboratory of Light Metal Materials,Hohhot 010051,China;China Foundry Association,Beijing 100044,China)

机构地区：[1]内蒙古工业大学材料科学与工程学院,内蒙古呼和浩特010051 [2]内蒙古自治区轻合金重点实验室,内蒙古呼和浩特010051 [3]中国铸造协会,北京100044

出　　处：《稀有金属》2024年第12期1681-1691,共11页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51764043);内蒙古自治区科技创新引导项目(KCBJ2018017);内蒙古自治区高校“青年科技英才”支持计划(NJYT-20-A16);内蒙古自然科学基金项目(2020MS05061)资助。

摘　　要：通过熔铸制备不同稀土Nd含量的Al-Zn-Mg-Cu-Zr-x Nd合金。采用光学显微镜(OM)、扫描电镜(SEM)、能谱(EDS)、X射线衍射(XRD)和力学性能测试,研究稀土Nd对铸态合金组织、非平衡共晶相的种类、形貌、各元素分布及力学性能的影响。结果表明:合金铸态组织为典型的树枝状晶,主要由α-Al基体、层片状Mg(Al,Cu,Zn)_(2)、η(MgZn_(2))、极少量浅灰色θ(Al_(2)Cu)相以及不规则块状Al_(8)Cu_(4)Nd相组成;添加稀土Nd引起溶质元素再分配,增加了成分过冷,使得合金的铸态组织得到明显细化;当Nd含量为0.2%时,具有最好的细化效果,综合性能最优,与不含Nd的合金相比,含0.2%Nd合金的二次枝晶臂平均间距和平均晶粒尺寸分别减小了48.1%(53.24μm)和50.5%(258.98μm);室温硬度增长了44.9%(HBW 105.2);室温抗拉强度和延伸率分别增长了34.3%(163 MPa)和44%(2.5%)。The microstructure and properties of Al-Zn-Mg-Cu-Zr aluminum alloy after deformation were mainly investigated,but the microstructure and properties of cast aluminum alloy were less reported.Appropriate microalloying could effectively enhance the microstructure and process properties of casting alloys,reduce casting defects and improve alloy properties,which can provide reference for the ingots of this series of deformed aluminum alloys.Rare earth elements were the most effective additive elements to optimize the comprehensive properties of ultra-high strength aluminum alloys.The interaction between rare earth(RE)elements and matrix elements to form and bulk compounds(AlZnMgCuRE).These dispersed phases uniformly distributed in the matrix can strongly pin dislocations and subgrain boundaries,which could significantly inhibit recrystallization,thus enhancing the stress corrosion resistance,exfoliation corrosion resistance and fracture toughness of the alloy.Rare earth Nd was rarely applied in Al-Zn-Mg-Cu-Zr series aluminum alloys,most of be illustrated by application of 2xxx aluminum alloys and Al-Si series alloys.The addition of Nd could change the morphology and size of the as-cast primary phase simultaneously,improve the heat resistance of aluminum alloys,which could provide a basis for exploring and developing new Al-Zn-Mg-Cu-Zr high strength aluminum alloys.Due to the negative effect of excessive rare earth content on the structure and properties of the alloy,the usual addition amount was 0.2%~0.4%.Optical microscope(OM),scanning electron microscope(SEM),energy spectrum analysis(EDS),X-ray diffraction(XRD)and Brinell hardness test were used to investigate the effect of rare earth Nd on the microstructure of the as-cast alloy,the variety and morphology of the non-equilibrium eutectic phase,the element distribution and the mechanical properties.Then the optimal addition amount of rare earth was selected.The results showed that the microstructure of as-cast alloy was typical dendritic crystal,which was mainly comp

关 键 词：Al-Zn-Mg-Cu-Zr铝合金 ND 晶粒细化 微观组织 显微硬度 

分 类 号：TG146.21[一般工业技术—材料科学与工程]