Anisotropy of localized corrosion in 7050-T7451 Al alloy thick plate  

7050-T7451铝合金厚板局域腐蚀的各向异性(英文)

作　　者：宋丰轩[1] 张新明[1] 刘胜胆[1] 韩念梅[1] 李东锋[1] 

机构地区：[1]中南大学 材料科学与工程学院,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2013年第9期2483-2490,共8页中国有色金属学报（英文版）

基　　金：Project(2012CB619502)supported by the National Basic Research Program of China

摘　　要：The corrosion anisotropy of 7050-T7451 A1 alloy thick plate in NaCI solution was investigated by immersion tests, slow strain rate testing （SSRT） technique, potentiodynamic and anode polarization measurements, optical microscropy （OM） and scanning electron microscopy （SEM） observations. The results show that the thick plate exhibits severe corrosion anisotropy due to the microstructure anisotropy. The observations of immersion surfaces together with the analysis of polarization curves reveal that the differences of the corrosion morphologies on various sections in this material are mainly related to the area fraction of the remnant second phase, and higher area fraction displays worst corrosion resistance. The stress corrosion cracking （SCC） susceptibility of different directions relative to the rolling direction is assessed by SSRT technique, ranked in the order： S direction 〉 L direction 〉 T direction. The result show that the smaller the grain aspect ratio, the better the corrosion resistance to SCC.采用持续浸蚀、慢应变速率拉伸、动态和阳极化测试以及光学和扫描电镜观察等对7050 T7451铝合金厚板局域腐蚀性能的各向异性进行研究。结果表明:7050 T7451铝合金厚板由于存在明显的微观组织各向异性而导致腐蚀性能的各向异性;合金不同截面腐蚀性能的差异是由基体内残余第二相分数的不同而引起的,残余第二相分数越大表面腐蚀越严重;不同方向样品的应力腐蚀敏感性顺序依次为S>L>T方向(慢应变速率拉伸测试结果),晶粒长宽比越小抗应力腐蚀性能越好。

关 键 词：7050-T7451 A1 alloy thick plate microstructure corrosion anisotropy 

分 类 号：TG174.3[金属学及工艺—金属表面处理]