(北京工业大学 材料科学与工程学院，北京 100124)
摘 要: 通过晶间腐蚀实验、剥落腐蚀实验和电化学测试，结合光学显微镜、扫描电镜和透射电镜等分析手段，研究高锌超高强铝合金在不同时效状态下的腐蚀行为。结果表明：双级过时效和回归再时效可提高合金的抗腐蚀能力，在3.5%NaCl(质量分数)溶液中测试的极化曲线也表现出相同的趋势。晶界析出相尺寸和形态是影响合金腐蚀性能的主要因素。双级过时效和回归再时效可使晶间析出相粗化且呈断续分布，使腐蚀不能连续发展，从而提高合金的耐蚀性能。超高强铝合金在含Cl-介质中腐蚀的发展动力学过程分为点蚀、晶间腐蚀和剥落腐蚀3个阶段。
关键字: 高锌超高强铝合金；晶间腐蚀；剥落腐蚀；极化曲线；晶界析出相
（School of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China）
Abstract:The influence of aging treatment on the intergranular corrosion and exfoliation corrosion susceptibility of the high Zn content super-high strength Al alloy was studied using optical microscopy (OM), scanning electron microscopy (SEM) and transmission election microscopy (TEM). The results show that the two-stage over-aging treatment and retrogression and re-aging treatment can improve the corrosion resistance of the super-high strength Al alloy, which are in accord with the results of polarization tests in 3.5%NaCl (mass fraction) solution. TEM observation shows that the size and morphology of precipitates at grain boundaries are the key factors responsible to the corrosion behavior of the alloy. After the two-stage over-aging treatment and retrogression and re-aging treatment, the precipitates at grain boundaries are coarse and discontinuous, which decreases the corrosion susceptibility of the alloy. Moreover, there are three stages of the corrosion development of the super-high strength Al alloy studied in Cl--containing media as pitting, intergranular corrosion and exfoliation corrosion.
Key words: high Zn content super-high strength Al alloy; intergranular corrosion; exfoliation corrosion; polarization curve; grain boundary precipitation
