中文摘要：

利用金相显微镜分析7A04铝合金半固态与铸态组织,对半固态与铸态7A04铝合金进行极化曲线与阻抗谱电化学测试分析,通过中性盐雾实验对比分析二者的质量损失率、腐蚀面积率和腐蚀坑深度,并采用激光共聚焦显微镜分析腐蚀形貌差异。结果表明：半固态初生α（Al）晶粒细小圆整,半固态试样的耐腐蚀性能优于铸态试样的,半固态试样腐蚀质量损失率较低,半固态试样的蚀坑平均深度及最大深度均小于铸态试样的。半固态工艺可显著提高7A04铝合金的耐腐蚀性能。

英文摘要：

The microstructure of semi-solid and as-cast 7A04 aluminum alloys was studied by optical microscopy,and the electrochemical corrosion behavior was investigated mainly by polarization curve and impedance spectroscopy.The mass loss rate,corrosion area rate and corrosion depth were researched by the salt spray corrosion,the corrosion morphologies were observed by laser scanning confocal microscopy.The results show that the semi-solid processing leads to a structure with fine and round grains（primary α（Al））,corrosion resistance of semi-solid sample is better than that of the as-cast sample.Both mass-loss and average corrosion depth of semi-solid sample are smaller than those of the as-cast sample.The semi-solid processing can improve the corrosion resistance of 7A04 aluminum alloy obviously.