【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)。更多还原

【Abstract】 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 Mg [2423] //[ 24 23],Mg(1010) //(10 1 0).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% NaCl solution,NZ30K-Er alloy’s corrosion current density is only 8.012 μA/cm2 and its corrosion mass loss rate is just 0.243 mg/(cm2·d).更多还原