摘要
采用双悬臂梁(DCB)试样,并通过阴极极化、扫描电镜(SEM)、透射电镜(TEM)和飞行时间二次离子质谱(ToF-SIMS)分析等手段,研究了不同时效状态下7050铝合金在3.5%Na Cl水溶液中的应力腐蚀行为。结果表明:7050铝合金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)。阴极极化电位E=-1100 m V时,合金的Iscc增加,DCB试样裂尖处氢离子流强度变大,氢在晶内扩散程度加深。微观组织分析表明:随着时效时间的延长,7050铝合金晶界析出相明显粗化,并且呈不连续分布。
The stress corrosion cracking( SCC) behavior of 7050 aluminum alloy at different aging states in 3. 5% sodium chloride aqueous solution was investigated by means of SCC tests using double cantilever beam( DCB) specimens,cathodic polarization,scanning electron microscopy( SEM),transmission electron microscopy( TEM) and time-of-flying second ion mass spectrometer( To F-SIMS) analysis. The results show that the susceptibility to SCC( Iscc) of 7050 aluminum alloy changed as following: Isccunder-aging( 135 ℃ × 8 h) ﹥ Isccpeakaging( 135 ℃ × 16 h) ﹥ Isccover-aging( 135 ℃ × 24 h). When applying a cathodic polarization potential E =- 1100 m V to the DCB specimens,the ion current intensity of hydrogen( IH+) near the crack tip and Isccincreases apparently,the degree of the diffusion of hydrogen into grains becomes more serious. The observation of microstructure indicates that the precipitates on the grain boundaries of7050 aluminum alloy become coarse and are sparsely distributed with the increasing of aging time.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2015年第3期90-95,共6页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51371039)
关键词
7050铝合金
时效
阴极极化
应力腐蚀
7050 aluminum alloy
aging
cathodic polariztion
stress corrosion cracking
