Er对Mg-Nd-Zn-Zr合金时效态组织和腐蚀性能的影响  

Effects of Er on microstructure and corrosion properties of Mg-Nd-Zn-Zr alloy

作　　者：梁叔全[1] 陈亮[1] 田志明[1] 官迪凯[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2012年第12期4646-4651,共6页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(50774097);国家自然科学基金创新研究群体科学基金资助项目(50721003)

摘　　要：采用X线衍射仪、光学显微镜、扫描电镜和透射电镜等分析测试方法研究Er对Mg-3Nd-0.2Zn-0.4Zr(NZ30K)合金时效态组织和腐蚀性能的影响,研究结果表明:添加0.5%(质量分数)Er元素并没有改变NZ30K合金峰时效析出相的种类,2种合金在200℃时达到峰时效都是因为基体里析出大量弥散分布的β″相,起到第二相强化的作用,β″相具有密排六方DO19结构,其与基体的取向关系为Mg[2423]β·//[2423]α-Mg,(1010)β·//(1010)α-Mg;由于细小的β″强化相的弥散分布,2种合金时效态表面由紧凑和均匀分布的细长条状颗粒组成,主要为Mg(OH)2,NZ30K-Er合金时效态的腐蚀产物膜更致密,所以NZ30K-Er合金时效态的耐腐蚀性能好于NZ30K合金时效态的耐腐蚀性能;NZ30K合金时效态具有优良的耐腐蚀性能,在5%的NaCl溶液中,其腐蚀电流密度仅为8.012μA/cm2,腐蚀质量损失速率仅为0.243 mg/(cm2·d)。The effects of Er addition on microstructure and corrosion properties of Mg-Nd-Zn-Zr alloy were investigated by X-ray diffractometry （XRD）, optical microscopy（OM）, scanning electron microscopy（SEM）, transmission electron microscope（TEM） etc. The results show that the addition of 0.5% Er does not change the type of precipitated phase in NZ30K alloy＇s peak-aged process. The reason why the two alloys reach their peak-aged hardness at 200 ℃ is that the precipitation of many uniform and homogeneously distributed fine β＂ phase in the Mg matrix, β＂ phase has a strengthening effect on Mg matrix and it has hcp DO19 structure. And its oriented relationships with Mg matrix is [2423]β＊∥[2423]α-Mg,（1010）β＊//（1010）α-Mg. Because of the homogeneous distribution of fine β＂ phase, the surface of both alloys is covered by compact and homogeneously distributed band-shaped fine particles（mainly Mg（OH）2）, the corrosion product film of NZ30K-Er aging state is more compact, and so the corrosion resistance properties of NZ30K-Er aging state is better. NZ30K-Er aging state has an excellent corrosion resistance property. Immersed in 5% NaC1 solution, NZ30K-Er alloy＇s corrosion current densi.ty is only 8.012 ixA/cm2 and its corrosion mass loss rate is just 0.243 mg/（cm2-d）.

关 键 词：ER Mg-Nd-Zn-Zr合金 时效态 组织 腐蚀性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]