摘要
通过显微组织分析、电化学试验和质量损失腐蚀试验等研究了不同含量的混合稀土(La, Ce)对7A04铝合金耐蚀性能的影响。结果表明:添加一定量的混合稀土后7A04铝合金的枝晶组织逐渐细化,第二相粒子随之减少,稀土含量为0.3%~0.5%时,晶粒细化效果较好,稀土含量大于1.2%时,铝合金的晶粒逐渐变得粗大,并沿晶界有块状第二相析出;铝合金的耐腐蚀性因稀土元素含量的不同,呈先增大后减小的变化规律,一定量的混合稀土能够有效抑制晶界处第二相的析出,从而减少基体金属与第二相粒子间的电偶腐蚀,降低铝合金电化学腐蚀的电流密度,在稀土含量为0.5%时7A04铝合金的耐腐蚀性较好;在3.5%NaCl溶液中铝合金发生了明显的点蚀,添加少量的稀土元素后铝合金表面的点蚀坑有明显的减少。
Effects of different contents of mixed rare earth(La, Ce) on corrosion resistance of 7 A04 aluminum alloy were studied by means of microstructure analysis, electrochemical test and mass loss corrosion test. The results show that after adding a certain amount of mixed rare earth, the dendrite structure of the 7 A04 aluminum alloy is gradually refined and the second phase particles are reduced. When the content of rare earth is 0.3%-0.5%, the grain refinement effect is better. When the content of rare earth is greater than 1.2%, the grain of the aluminum alloy gradually becomes coarse and massive second phase precipitates along the grain boundary. The corrosion resistance of the aluminum alloy increases first and then decreases with increasing the content of rare earth elements. A certain amount of mixed rare earth can effectively inhibit the precipitation of the second phase at the grain boundary, so as to reduce the galvanic corrosion between the base metal and the second phase particles and decrease the current density of electrochemical corrosion of the aluminum alloy. The corrosion resistance of the 7 A04 aluminum alloy is better when the content of rare earth is 0.5%. After immersion in 3.5% NaCl solution, the aluminum alloy has obvious pitting corrosion, and the pitting corrosion on the surface of the aluminum alloy after adding a small amount of rare earth elements are significantly reduced.
作者
张美丽
张磊军
刘壮壮
韩茜
代卫丽
李春
窦宝捷
ZHANG Mei-li;ZHANG Lei-jun;LIU Zhuang-zhuang;HAN Xi;DAI Wei-li;LI Chun;DOU Bao-jie(Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources,Shangluo University,Shangluo 726000,China;Material Corrosion and Protection Key Laboratory of Sichuan Province,Sichuan University of Science and Engineering,Zigong 643000,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2022年第5期40-48,共9页
Transactions of Materials and Heat Treatment
基金
陕西省教育厅专项科研计划资助项目(20JK0618)
陕西省大学生创新创业训练计划项目(S202011396087)
商洛市科技局科学技术研究发展计划项目(2020-Z-0083)
材料腐蚀与防护四川省重点实验室开放基金资助(2021CL17)。
关键词
7A04铝合金
稀土
显微组织
极化曲线
电化学阻抗
质量损失腐蚀
7A04 aluminum alloy
rare earth
microstructure
polarization curve
electrochemical impedance
weightlessness corrosion
