时效对7056铝合金在EXCO溶液中剥落腐蚀行为的影响  

Effect of Aging on Exfoliation Corrosion Behavior of 7056 Alloy in EXCO Solution

作　　者：马灿[1,2] 谭澄宇[1,2] 覃思思[2] 李杰[1,2] 蒋建辉[2] 

机构地区：[1]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083 [2]中南大学材料科学与工程学院,长沙410083

出　　处：《腐蚀与防护》2016年第2期93-99,共7页Corrosion & Protection

基　　金：国家重点基础研究发展计划项目(2005CB623705)

摘　　要：研究了7056铝合金经120℃单级时效与120℃×4h+165℃×8h双级时效后在EXCO溶液中的剥落腐蚀行为。观察了不同时效状态7056合金表面腐蚀形貌随浸泡时间延长的变化,并进行腐蚀等级评定;采用CHI660C电化学工作站检测了7056合金在EXCO溶液中的极化曲线与电化学阻抗谱。借助透射电镜观察了不同时效状态下7056合金的组织形貌特征,并就微观组织对剥落腐蚀行为的影响进行了深入的分析。结果表明:在120℃单级时效,随时效时间延长,7056合金抗剥落腐蚀能力增加;与120℃×100h长时间时效相比,经120℃×4h+165℃×8h时效后,7056合金具有较好的抗剥落腐蚀能力。The exfoliation corrosion behavior in EXCO solution of 7056 Al alloy after 120℃ single-stage and 120℃×4 h＋165℃×8 h two-stage aging treatment was studied. The corrosion morphology change of 7056 Al alloy in different aging states with the extension of soaking time was observed, and its corrosion rating was ranked. The polarization curves and electronchemical impedance spectroscopy （EIS） of 7056 Al alloy in EXCO solution were measured by electrochemical workstation CHI660C. The microstructure of 7056 alloy in different aging states was observed by TEM and the effect of microstructure on exfoliation corrosion behavior was analyzed deeply. The results show that with the prolongation of aging time, the exfoliation corrosion resistance of 7056 Al alloy increased in 120℃ single-stage aging. Compared with 120℃×100 h long time aging, 7056 alloy aged at 120℃×4 h＋165℃×8 h had better exfoliation corrosion resistance.

关 键 词：7056铝合金 时效 剥落腐蚀 电化学阻抗谱 

分 类 号：TG171[金属学及工艺—金属表面处理] TG146.21[金属学及工艺—金属学]