稀土元素Er对高锌铝合金组织和性能的影响  

Effect of Rare Earth Element Er on Microstructure and Properties of High Zinc Aluminum Alloy

作　　者：张照超 黄福祥[1] 阮海光 钟明君[1] 

机构地区：[1]重庆理工大学材料科学与工程学院,重庆400054

出　　处：《重庆理工大学学报（自然科学）》2017年第8期86-92,共7页Journal of Chongqing University of Technology：Natural Science

基　　金：重庆市社会民生科技创新专项(cstc2016shmszx80019)

摘　　要：采用光学显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)、X衍射射线分析仪(XRD)、显微硬度计等仪器研究了加入不同含量的稀土元素Er对高锌铝合金(Al Zn32)的铸态组织及硬度的影响规律,并分析探讨了其作用机理。研究结果表明,添加适量的稀土元素Er能有效细化高锌铝合金的铸态组织,粗大的初生富铝α等轴晶晶粒转变为细小、均匀的等轴晶晶粒;合金的等轴晶晶粒随Er含量的增加呈先减小后增大趋势,当加入0.2%Er时,等轴晶晶粒尺寸最小约为30~40μm。合金硬度随Er含量的增加呈先增大后减小的趋势,当添加0.2%Er时,硬度达到极大值127 HV。稀土元素Er部分以块状的Al3Er(Ti,Cr)金属间化合物的形式分布于晶界,少部分的Er固溶于α基体中。Influences of the addition of different content of rare earth Er on as-cast microstructure and hardness of high zinc aluminum alloys（Al Zn32） were studied by optical microscopy（OM）,scanning electron microscopy（SEM）,energy spectrum analyzer（EDS）,X-ray diffraction analyzer（XRD）,vickers hardness tester and its refinement mechanism was discussed. The results indicate that the addition of an appropriate amount of rare earth element Er can effectively refine the as-cast microstructure of alloys,and the shape of coarse primary α-Al phase dendrites is transformed into fineand homogeneous equiaxed crystal. The equiaxed grains of the alloy has firstly been decreased and then increased with the increase of Er content. When the content of rare Er reaches 0. 2%,the average size of equiaxed crystal is about 30 ~ 40μm. The hardness of alloy has firstly been increased and then decreased with the increase of Er content. When the addition of rare Er is 0. 2%,the hardness arrives at maximum 127 HV. Some Rare Er is distributed in the grain boundary in the form of a bulk Al3Er（Ti,Cr） intermetallic compound,and a small amount of Er is dissolved in the α matrix.

关 键 词：铝锌合金 稀土元素ER 合金硬度 铸态组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]