Mg、Cu元素能够显著提高Al-Si合金的强度， 但同时也会影响合金耐腐蚀性能。 为探究Mg、Cu元素对 Al-Si 合金的影响，利用电化学测试，以Al-7%Si-0.3%Mg(质量分数)合金为基础，分析了Mg、Cu元素添加量对 T6热处 理后Al-Si-Mg-Cu 合金耐蚀性的影响。 结果表明，随着Mg、Cu元素含量增加和腐蚀时间增长，Al-7%Si-Mg-Cu合金阻 抗值下降，Nyquist 电容环半径减小，腐蚀电流密度增大，合金耐腐蚀性能呈下降趋势。Mg元素含量从0.3%增加到0.5% (质量分数)，腐蚀电流密度增加了3.5%；Cu含量从0%增加到0.65%(质量分数)，腐蚀电流密度增加10.1%，表明随着 Mg、Cu 含量的少量增加，合金耐腐蚀性能略有下降。 尽管Mg、Cu元素在时效过程析出的纳米相有加速腐蚀的作用，但 少量Mg、Cu的加入对合金产生的腐蚀破坏较轻。

Mg and Cu can significantly improve the strength of Al-Si alloys, but at the same time, they also affect their corrosion resistance. To explore the influence of Mg and Cu on Al-Si alloys, which are based on an Al-7 wt.% Si-0.3 wt.% Mg alloy, electrochemical testing methods were used to analyse the effects of the addition of Mg and Cu on the corrosion resistance of Al-Si-Mg-Cu alloys after T6 heat treatment. The results show that with increasing contents of Mg and Cu and increasing corrosion time, the impedance value of the Al-7 wt.%Si-Mg-Cu alloy decreases, the radius of the Nyquist capacitance loop decreases, the corrosion current density increases, and the corrosion resistance of the alloy tends to decrease. When the content of Mg increases from 0.3 wt.% to 0.5 wt.%, the corrosion current density increases by 3.5%, and when the content of Cu increases from 0 wt.% to 0.65 wt.%, the corrosion current density increases by 10.1%. This indicates that with a slight increase in the contents of Mg and Cu, the corrosion resistance of the alloy slightly decreases. Although the nanophases precipitated by Mg and Cu during the aging process accelerate corrosion, the corrosion damage caused by the addition of a small amount of Mg and Cu to the alloy is relatively light.