(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 通过显微硬度测试、晶间腐蚀(IGC)、交流阻抗实验和透射电镜(TEM)观察，研究了2022和2139合金在T6(175 ℃)时效过程中的时效硬化特征、晶间腐蚀行为和微观组织演化。结果表明：2022和2139合金在175 ℃达到峰值时效的时间分别为20 h和15 h。两种合金在峰时效状态下其晶间腐蚀最为敏感；过时效状态下都产生大面积腐蚀坑而未观察到明显的晶间腐蚀。然而欠时效状态下2022合金的抗腐蚀能力优于2139合金的；峰时效状态下2022合金的抗腐蚀能力明显低于2139合金的，这与两种合金在不同的时效状态下析出相的种类、分布和形貌有关。
关键字: 2022合金；2139合金；Ag；晶间腐蚀；交流阻抗
2××× series Al-alloys with high Cu/Mg ratio
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effects of artificial aging treatments on the aging hardening characteristics, intergranular corrosion (IGC) and microstructural evolution of 2022 and 2139 alloy were investigated by microhardness test, IGC test, electrochemical impedance spectroscopy (EIS) and transmission electron microscopy (TEM). The results show that the time to peak aging of 2022 and 2139 alloys during aging at 175 ℃ are 20 h and 15 h, respectively. Both alloys get to the maximal susceptibility of IGC at the peak-aged condition while no obvious IGC behavior but some stable pitting corrosion is found at the over-aged condition. The corrosion resistance of 2022 alloy at the under-aged condition is better than that of 2139 alloy, while under the peak-aged condition, the corrosion resistance of 2022 alloy is obviously the worse, which can be contributed to the type, distribution and morphology of the precipitations.
Key words: 2022 alloy; 2139 alloy; Ag; intergranular corrosion; electrochemical impedance spectroscopy
