(1. 常州大学 材料科学与工程学院，常州 213164；
2. 北京科技大学 环境断裂教育部重点实验室，北京 100083)
摘 要: 采用阴极极化、慢应变速率拉伸试验(SSRT)和定氢仪研究阴极极化对7050铝合金应力腐蚀行为的影响。结果表明：当阴极极化电位高于-1100 mV时，7050铝合金的应力腐蚀敏感性(Iscc)随着极化电位的负移而升高；而当阴极极化电位低于-1100 mV时，Iscc则随着极化电位的负移而下降。外加极化电位对不同时效状态7050铝合金Iscc的影响程度不同，即阴极极化对欠时效状态下铝合金的Iscc影响显著，对过时效状态铝合金Iscc的影响最小，对峰时效状态下铝合金Iscc的影响居中。铝合金的应力腐蚀机理为阳极溶解和氢脆共同作用，且氢对铝合金应力腐蚀的作用随着氢浓度的增加而增加。
关键字: 7050铝合金；应力腐蚀；氢脆；阴极极化；慢应变速率拉伸
（1. School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China;
2. Key Laboratory of Environment Fracture, Ministry of Education,
University of Science and Technology Beijing, Beijing 100083, China）
Abstract:The effects of cathodic polarization on stress corrosion behavior of 7050 aluminum alloy were studied by cathodic polarization, slow strain rate test (SSRT) and hydrogen determinator. The results show that the stress corrosion cracking (SCC) susceptibility (Iscc) of 7050 aluminum alloy increases with shifting negatively the polarization potential when the cathodic polarization potential is higher than -1100 mV, whereas it decreases when the cathodic polarization potential is lower than -1100 mV. The extent for the effect of polarization potential on Iscc is different among the 7050 aluminum alloys with various aging states. Cathodic polarization has greater effect on SCC of under-aged 7050 aluminum alloy than on that of over-aged 7050 aluminum alloy, and the peak aged 7050 aluminum alloy is in the middle. The SCC mechanism of aluminum alloy is a combination of anodic dissolution with hydrogen embrittlement, and the effect of hydrogen on SCC of aluminum alloy increases with increasing the hydrogen concentration.
Key words: 7050 aluminum alloy; stress corrosion; hydrogen embrittlement; cathodic polarization; slow strain rate test
