添加稀土Gd对Mg-6Al镁合金组织和耐蚀性的影响

Mg-6Al镁合金具有较好的铸造性能和力学性能,目前鲜见单一稀土元素对其腐蚀性能影响的报道。通过合金制备、微观组织分析和耐蚀性测试等方法研究了稀土Gd添加量对Mg-6Al镁合金微观组织和耐蚀性能的影响。OM、SEM、EDS、XRD分析结果表明,稀土Gd的添加改善并细化了Mg-6Al合金的铸态组织,形成杆状或块状的Al2Gd新相;动电位极化、浸泡试验等测试结果表明Gd的添加显著提高了Mg-6Al合金在3.5%NaCl溶液中的耐腐蚀性能,Mg-6Al-2%Gd镁合金的腐蚀速度最小,为0.83 mm/a,且腐蚀后组织较为致密,腐蚀产物和腐蚀坑均变小,Mg-6Al-x Gd合金的腐蚀产物主要为Mg(OH)2。

Effects of Gd Addition on the Microstructure and Corrosion Resistance of Mg-6Al Magnesium Alloy

The effects of Gd addition on the microstructure and corrosion resistance of Mg-6 Al magnesium alloy were studied by alloy preparation,microstructure analysis and corrosion resistance testing. Results of OM,SEM,EDS and XRD showed that as-cast microstructure of Mg-6 Al magnesium alloy was improved and refined due to the addition of Gd,and the new rod and block phases of Al2 Gd were observed. The polarization curves and immersion testing results showed that the addition of Gd could significantly improve the anti-corrosion properties of Mg-6 Al in 3.5%Na Cl solution. The corrosion rate of Mg-6 Al-2%Gd was the smallest( 0.83 mm/a),and the corrosion morphology of Mg-6 Al-2%Gd alloy became very tight with less corrosion products and smaller corrosion pits. Moreover,the corrosion products of Mg-6 Al-x Gd were mainly Mg( OH)2.