摘要
采用阴极极化、扫描电子显微镜(SEM)和定氢仪分析,研究了不同时效状态的7050铝合金C-环在3.5%Na Cl水溶液中的应力腐蚀行为。结果表明:7050铝合金恒位移试样C-环时效后的应力腐蚀敏感性(Iscc)变化规律为:Iscc欠时效(135℃/8 h)>Iscc峰时效(135℃/16 h)>Iscc过时效(135℃/24 h)。在一定范围内施加阴极极化电位,7050铝合金材料发生阴极腐蚀,从而促进裂纹萌生。对相同时效状态的7050铝合金,C-环断口的氢渗透速率随着极化电位的负移而增加,从而导致合金的Iscc增加。
The effect of cathodic polarization on stress corrosion cracking(SCC) behavior of Cring specimens of 7050 aluminum alloys of different aging states in 3.5% sodium chloride aqueous solution has been investigated, then the hydrogen content of the tested samples was measured by a hydrogen analyzer and the fractured alloy samples were examined by means of scanning electron microscope(SEM). The results showed that according to their aging states, the degree of susceptibility to SCC(Iscc) of 7050 aluminum alloy may be ranked as following: Isccof under-aging(135 ℃/8 h)>Isccof peak-aging(135 ℃/16 h)>Isccof over-aging(135 ℃/24 h). When applying a cathodic polarization potential to C-ring specimen, the cathodic corrosion of 7050 aluminum alloy may promote the crack growth. For 7050 aluminum alloys after the same aging treatment, the hydrogen permeation rate of the C-ring fracture surface increased with shifting negatively the cathodic polarization, thus resulting in the increase of Iscc.
出处
《腐蚀科学与防护技术》
CAS
CSCD
北大核心
2015年第3期249-253,共5页
Corrosion Science and Protection Technology
基金
国家自然科学基金项目(51371039)资助
关键词
7050铝合金
阴极极化
C-环试样
应力腐蚀
7050 aluminum alloy,cathodic polarization,C-ring specimen,stress corrosion cracking(SCC)
