LY6铝合金的局部腐蚀行为研究  

Local Corrosion Behaviors of LY6 Aluminum Alloy in CI^- Environment

作　　者：陶斌武[1] 李松梅[1] 刘建华[1] 

机构地区：[1]北京航空航天大学材料科学与工程学院,北京100083

出　　处：《材料保护》2004年第11期15-16,47,共3页Materials Protection

摘　　要：　探讨LY6合金的局部腐蚀行为对扩大其应用范围意义重大,采用加速腐蚀试验和微观腐蚀形貌观察等方法,研究了经自然时效处理的LY6铝合金在含Cl-的典型环境中的点蚀、晶间腐蚀、应力腐蚀断裂和剥蚀等局部腐蚀行为,并讨论了它们的机理和相互关系。在试验环境下,LY6铝合金对点蚀、晶间腐蚀、剥蚀和应力腐蚀断裂都存在敏感性,合金中S相(Al2CuMg)、θ相(CuAl2)及MnAl6等第二相的存在是发生上述局部腐蚀的根本原因。研究表明,合金的剥蚀是一个从点蚀发展到晶间腐蚀,然后在应力协同作用下发生破坏的过程。恒载荷应力腐蚀拉伸法和断口形貌观察发现,LY6铝合金应力腐蚀断裂是由于阳极溶解作用的结果。Local corrosion behaviors of LY6 aluminum alloy after natural aging treatment in solution containing Cl^-,such as pitting corrosion, intergranular corrosion, exfoliation corrosion (EXCO) and stress corrosion cracking (SCC), were studied as well as their mechanisms and correlation. LY6 aluminum alloy is susceptible to pitting corrosion, intergranular corrosion,EXCO and SCC in the testing environment, which is essentially due to the existence of second phases, such as S phase (Al_2CuMg) , θ phase (CuAl_2 ) and MnAl6 phase. The exfoliation of alloy happens from original pitting to intergranular corrosion and with cooperation of stress. By constant load tensile test and fracture analysis, SCC of LY6 aluminum alloy is owing to the anodic dissolution effect.

关 键 词：Al-Mg-Cu合金 应力腐蚀断裂(SCC) 剥蚀 晶间腐蚀 点蚀 

分 类 号：TG172.9[金属学及工艺—金属表面处理]