Comparative study on corrosion behavior of as-cast and extruded Mg-5Y-7Gd-1Nd-0.5Zr alloy in 5% NaCl aqueous solution  

铸态与挤压态Mg-5Y-7Gd-1Nd-0.5Zr合金在5% NaCl水溶液中的腐蚀行为(英文)

作　　者：张新[1,2,3] 张奎[1] 李兴刚[1] 邓霞[1] 李宏伟[2,3] 张宝东[2,3] 王长顺[2,3] 

机构地区：[1]北京有色金属研究总院、有色金属材料制备加工国家重点实验室,北京100088 [2]北京北方车辆集团有限公司工艺研究所,北京100072 [3]北京市特种车辆部件先进制造与评估工程技术研究中心,北京100072

出　　处：《Transactions of Nonferrous Metals Society of China》2012年第5期1018-1027,共10页中国有色金属学报（英文版）

基　　金：Project (2011BAE22B01) supported by the National Key Technology R&D Program of China

摘　　要：The corrosion behaviours of Mg-5Y-7Gd-1Nd-0.5Zr magnesium alloys prepared by as-casting and extrusion were investigated in 5% NaCl aqueous solution by immersion and electrochemical tests. The microstructure indicates the mean grain size of 15 μm for the extruded and 100 μm for the as-cast Mg-5Y-7Gd-1Nd-0.5Zr magnesium alloys. The corrosion morphology of as-cast sample shows pitting corrosion and little filiform corrosion, but that of the extruded sample shows pitting corrosion at the initial stage. The corrosion rate of extruded sample is higher than that of as-cast Mg-5Y-7Gd-1Nd-0.5Zr alloy according to the immersion test. The second phases containing RE acting as cathodes improve the corrosion properties. The corrosion potentials of as-cast and extruded Mg-5Y-7Gd-1Nd-0.5Zr alloys are -1.658 V and -1.591 V, respectively. The origins of the distinctive corrosion behavior of as-cast and extruded Mg-5Y-7Gd-1Nd-0.5Zr Mg alloys were discussed.在5%NaCl水溶液中通过浸泡和电化学测试研究铸态与挤压态Mg-5Y-7Gd-1Nd-0.5Zr镁合金的腐蚀性能。铸态和挤压态Mg-5Y-7Gd-1Nd-0.5Zr镁合金的平均晶粒尺寸分别为100μm和15μm。在腐蚀初期,铸态合金的腐蚀形貌为点蚀和少量丝状腐蚀,挤压态合金的腐蚀形貌为点蚀。挤压态合金的腐蚀速率大于铸态合金的腐蚀速率。包含稀土的第二相在合金中作为阴极,改善了合金的腐蚀性能。铸态与挤压态合金的腐蚀电位分别为-1.658V和-1.591V。探讨了铸态与挤压态合金腐蚀性能不同的原因。

关 键 词：Mg-5Y-7Gd-1Nd-0.5Zr magnesium alloy corrosion morphology polarization curve 

分 类 号：TG172.5[金属学及工艺—金属表面处理]