(中南大學 材料科學與工程學院，長沙 410083)
摘 要: 通過顯微硬度測試、晶間腐蝕(IGC)、交流阻抗實驗和透射電鏡(TEM)觀察，研究了2022和2139合金在T6(175 ℃)時效過程中的時效硬化特征、晶間腐蝕行為和微觀組織演化。結(jié)果表明：2022和2139合金在175 ℃達到峰值時效的時間分別為20 h和15 h。兩種合金在峰時效狀態(tài)下其晶間腐蝕最為敏感；過時效狀態(tài)下都產(chǎn)生大面積腐蝕坑而未觀察到明顯的晶間腐蝕。然而欠時效狀態(tài)下2022合金的抗腐蝕能力優(yōu)于2139合金的；峰時效狀態(tài)下2022合金的抗腐蝕能力明顯低于2139合金的，這與兩種合金在不同的時效狀態(tài)下析出相的種類、分布和形貌有關(guān)。
關(guān)鍵字: 2022合金；2139合金；Ag；晶間腐蝕；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
