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采用静态失重法、扫描电子镜及能谱分析、电化学测试法等方法研究了稀土元素Sm(0~0.9%)对AM60镁合金的铸态组织和耐腐蚀性的影响。结果表明:微量稀土元素Sm可细化AM60镁合金中β-Mg17Al12相,合金中的β-Mg17Al12相由粗大、连续树枝状分布逐渐转变为细小、弥散的颗粒状均匀分布。同时,合金中生成了大量弥散分布的富Sm的稀土相。这些富Sm的稀土相使合金的耐腐蚀性得到显著提高,当稀土Sm含量为0.6%时,合金腐蚀速率为0.6mg·cm-2·d-1,仅为基体合金的37%。随AM60镁合金中稀土元素Sm含量的增加,合金腐蚀电位逐渐升高,腐蚀电流减小。
The effects of rare earth element Sm (0 ~ 0.9%) on the as-cast microstructure and corrosion resistance of AM60 magnesium alloy were investigated by static weight loss method, scanning electron microscopy and energy dispersive spectroscopy, electrochemical test and other methods. The results show that the trace rare earth element Sm can be used to refine the β-Mg17Al12 phase in AM60 magnesium alloy. The β-Mg17Al12 phase in the alloy gradually changes from coarse and continuous dendritic distribution to fine and dispersed uniformly distributed particles. At the same time, a large number of Sm-rich rare earth phases were formed in the alloy. The corrosion resistance of these Sm-rich rare earth alloys is significantly improved. When the Sm content is 0.6%, the corrosion rate of the alloy is 0.6mg · cm-2 · d-1, which is only 37% of the base alloy. With the increase of the content of rare earth element Sm in AM60 magnesium alloy, the corrosion potential of the alloy gradually increases and the corrosion current decreases.