稀土Er对ZK21镁合金组织的影响  

Effects of rare earth Er on microstructure of ZK21 alloy

作　　者：张静[1] 袁付庆[1] 豆雨辰[1] 张旭峰[1] 汤爱涛[1] 

机构地区：[1]重庆大学材料科学与工程学院国家镁合金材料工程技术研究中心,重庆400044

出　　处：《材料热处理学报》2011年第11期94-98,共5页Transactions of Materials and Heat Treatment

基　　金：国家杰出青年基金(50725413);重庆市杰出青年基金(CSTC;2008BA4036);重庆大学大型设备开放基金

摘　　要：研究了添加稀土Er(0～4.0%)对半连续铸造ZK21合金铸态和均匀化态组织的影响。结果表明,稀土Er的添加可有效细化铸态组织,加入2.0%的Er使合金的平均晶粒尺寸由94μm细化至62μm,减小了34%。Er在均匀化态合金中部分固溶于基体中,部分与Mg、Zn元素形成热稳定Mg-Zn-Er三元化合物相;当稀土含量高于0.5%时,合金中不存在二元Mg-Zn相。随着稀土含量的增加,Er在基体中的固溶度增大,化合物的体积百分数增多,与此同时,Zn在基体中的固溶度减少。合金的硬度在Er含量为2.0%时达到最大,这是基体中Zn、Er元素固溶强化和析出相强化的综合作用结果。Effects of rare earth Er addition in the range of 0-4.0% on as-cast and as-homogenized microstructure of semi-continuous-cast ZK21 alloy were investigated.The results show that the addition of Er can effectively refine the as-cast microstructure,the average grain size decreases by 34%,from 94 μm to 62 μm,with the addition of 2.0% Er.Part of the added Er is dissolved in the matrix and the other reacts with Mg and Zn to form thermal stable Mg-Zn-Er ternary compounds.There is no binary Mg-Zn compound when the content of Er is higher than 0.5%.With increasing of the Er content,the concentration of Er in the matrix and the volume fraction of the compounds increase,in the mean time,the concentration of Zn in the matrix decreases.The hardness reaches its peak value for the alloy with 2.0% Er,which is attributed to the combined effects of the solid solution strengthening of element Zn and Er and the precipitation strengthening.

关 键 词：镁合金 稀土 均匀化 显微组织 硬度 

分 类 号：TG146.22[一般工业技术—材料科学与工程]