Sn对Mg-6Al-1.2Y-0.9Nd镁合金组织和耐蚀性能的影响

EFFECTS OF Sn ON MICROSTRUCTURES AND CORROSION RESISTANCE OF Mg-6Al-1.2Y-0.9Nd MAGNESIUM ALLOY

用静态失重法、金相显微镜、扫描电子显微镜等方法研究了不同含量的Sn对Mg-6Al-1.2Y-0.9Nd镁合金的微观组织以及在3.5%NaCl腐蚀介质中的腐蚀速率和表面腐蚀形貌的影响。结果表明,添加1%Sn时,合金的晶粒得到了明显的细化,组织和成分更加均匀;当Sn含量大于1%时,合金的析出相增多,并出现粗化、偏聚的趋势。在NaCl溶液中,合金的腐蚀速率均随着Sn含量的增加呈现先降低后增加的趋势,其中当Sn含量为1%时合金的腐蚀速率均达到最低,耐蚀性能得到明显地改善。

Effects of Sn addition on corrosion rate of Mg-6Al-1.2Y-0.9Nd magnesium alloy in 3.5%NaCl solution were studied by the static mass-loss tests.The microstructures of the alloys were observed by optical microscope and the morphologies of corrosion surface were analyzed with scanning electron microscopy.The results indicated that with the addtion of 1%Sn,the crystal grain size of the Mg-6Al-1.2Y-0.9Nd magnesium alloy was obviously refined,the microstructure was more homogeneous.But when the addition of Sn is more than 1%,the precipitates increase and they cause the trend of coarsening and segregation.Furthermore,in NaCl solution the corrosion rate of Mg-6Al-1.2Y-0.9Nd magnesium alloy decreases firstly and then increases with the increase of Sn content.With the addtion of 1%Sn,the corrosion rate of the alloy was the lowest,and the corrosion resistance was improved remarkably.