固溶制度对7050铝合金微观组织和腐蚀性能的影响  

Effects of Solution Heat Treatment on Microstructure and Corrosion Properties of 7050 Al Alloy

作　　者：宋丰轩[1,2] 张新明[1,2] 刘胜胆[1,2] 白谭[1,2] 韩念梅[1] 谭季波[1] 

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

出　　处：《航空材料学报》2013年第4期14-21,共8页Journal of Aeronautical Materials

基　　金：国家重点基础研究发展计划(973计划)项目(2012CB619502)

摘　　要：采用光学显微镜(OA)、扫描电镜(SEM)、透射电镜(TEM)等手段和电化学、浸蚀、慢应变速率拉伸(SSRT)等测试方法,研究不同固溶热处理制度对7050铝合金板材微观组织和腐蚀性能的影响。结果表明:单级固溶将η(MgZn2)相完全溶入Al基体中,而S(Al2CuMg)相仍然大量存在,固溶度低,时效后晶内析出密度低;双级固溶使S相部分溶解,合金晶粒长大,再结晶分数高;逐级固溶使η和S相完全溶解,合金充分回复,时效后晶内析出密度高,再结晶分数低;不同固溶+T6时效态合金的抗应力腐蚀性能从大到小依次为逐级固溶>双级固溶>单级固溶。The effects of different solution heat treatments on the microstructure and corrosion resistance of 7050 A1 alloy hot-rolled plate were investigated by optical microscopy （ OM）, scanning electron microscopy （ SEM）, transmission electron microscope （ TEM）, electrochemical measurements, immersion corrosion tests and slow strain rate techniques （SSRT）. The results show that η （MgZn2 ） phase is fully dissolved into A1 matrix after the single-step solution heat treatment, while S （A12CuMg） phase isn＇t dissolved at all. As a result, the supersaturation degree of the alloy is low and the precipitation density of second phase in the A1 matrix after aging treatment is small. Through the two-step solution treatment, S phase is partially dissolved and the size of recrystallization grains in the alloys grows larger resulting in the increase of recrystallization volume fraction. By treating with step-to-step solution, η and S phase are completely dissolved into the matrix contributing to the high precipitation density in the A1 matrix after aging treatment. Meanwhile, the alloy with low reerystallization fraction is obtained because of full recovery. The resistance to stress corrosion cracking （SCC） for the samples with solution and aging treatments decreases in the order： step-to-step solution 〉 two-step solution 〉 single-solution.

关 键 词：7050铝合金 固溶 电化学 腐蚀性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]