Zn对均匀态Mg-4Sn合金组织及耐蚀性能的影响

Effects of Zn Addition on Microstructure and Corrosion Properties of Homogenized Mg-4Sn Alloys

研究了添加1%的Zn对均匀态Mg-4Sn合金微观组织及耐蚀性能的影响。利用OM、SEM、XRD、析氢失重试验以及极化曲线来分析两种合金的耐蚀性能。结果表明,Zn细化了Mg-4Sn合金的晶粒尺寸,由179.09μm减小到91.53μm,有颗粒状和长条状的Mg_(2)Sn相弥散分布于α-Mg基体中,Zn以固溶的方式存在于基体中。析氢失重测试结果表明,Zn提高了Mg-4Sn合金的耐蚀性能,这主要归因于Mg-4Sn-1Zn合金晶粒细小,并且Zn的添加使Mg_(2)Sn相分布更加均匀。极化曲线测得Mg-4Sn、Mg-4Sn-1Zn的自腐蚀电流密度分别为2.332×10^(-5)、3.848×10^(-6)μA/cm^(2)。因此,Mg-4Sn-1Zn合金的耐蚀性高于Mg-4Sn合金。

The influence of 1% Zn element on microstructure and corrosion resistance of homogenized Mg-4Sn alloy was investigated.The corrosion resistance of alloys was analyzed by OM,SEM,XRD,hydrogen loss experiment and polarization curve.The results indicate that the grain of Mg-4Sn alloy is refined by Zn addition,which is reduced from 179.09μm to 91.53μm.The granular and long striped Mg_(2)Sn phase is dispersedly distributed in α-Mg matrix,and Zn exists in the matrix as a solid solution.Hydrogen loss test results reveal that the corrosion resistance of Mg-4Sn is enhanced by Zn addition,which is mainly attributed to the fine grain of Mg-4Sn-1Zn alloy,leading to the evenly distribution of Mg_(2)Sn phase.Polarization curves demonstrate that the self-corroded current density of Mg-4Sn and Mg-4Sn-1Zn are 2.33×10^(-5)μA/cm^(2)and 3.848×10^(-6)μA/cm^(2),respectively,indicating the superior corrosion resistance of Mg-4Sn-1Zn alloy to that of Mg-4Sn.