盐雾环境下6061-T6铝合金腐蚀疲劳失效机理研究  

Studies on corrosion fatigue failure mechanism of 6061-T6 aluminum alloy in salt spray environment

作　　者：王飞 宋奕 何佰毅 Wang Fei;Song Yi;He Baiyi(Pipe China North West Company,Yinchuan 750001,China)

机构地区：[1]国家管网集团西北公司,宁夏银川750001

出　　处：《电镀与精饰》2025年第4期33-41,57,共10页Plating & Finishing

摘　　要：结构件在服役过程中受到交变载荷和腐蚀因素的影响,会加快其腐蚀疲劳失效过程,大幅缩短其服役寿命。本文针对6061-T6铝合金,通过盐雾环境下的腐蚀疲劳试验,结合微观形貌观测、元素成分分析、晶粒结构表征等方法,研究盐雾浓度以及加载频率对其腐蚀疲劳性能的影响,分析其失效机理。结果表明:在3.5 wt.%~5.0 wt.%盐雾浓度区间,材料的疲劳寿命下降了52.43%~66.32%,在低浓度区间,腐蚀产物和NaCl结晶颗粒阻塞裂纹尖端延缓裂纹扩展速率,材料疲劳寿命呈上升趋势;随着盐雾浓度进一步升高,腐蚀反应速率加快,试样表面腐蚀加重,应力集中现象明显,加剧了裂纹源形成,材料疲劳寿命逐渐下降。在3.5 wt.%盐雾环境中,加载频率从5 Hz上升至10 Hz,增加了材料的位错密度,促进腐蚀介质渗透,加快了腐蚀进程,导致材料腐蚀疲劳寿命下降了15.13%。Structural components are subjected to alternating loads and corrosive factors during service,which accelerate their corrosion fatigue failure process and significantly shorten their service life.This study focuses on 6061-T6 aluminum alloy,conducting corrosion fatigue tests in the salt spray environment,combined with methods such as microstructural observation,elemental composition analysis,and grain structure characterization,to investigate the effects of salt spray concentration and loading frequency on its corrosion fatigue performance and analyze the failure mechanism.The results indicate that within the salt spray concentration range of 3.5 wt.%to 5.0 wt.%,the fatigue life of the material decreased by 52.43%to 66.32%.At lower concentrations,corrosion products and NaCl crystal particles obstruct the crack tip,slowing the crack propagation rate and leading to an increase in material fatigue life.As the salt spray concentration further increases,corrosion reaction rate accelerates.The corrosion on the sample surface intensifies,and stress concentration becomes more pronounced.This exacerbates the formation of crack sources,gradually reducing the fatigue life of the material.Under a 3.5 wt.%salt spray environment,increasing the loading frequency from 5 Hz to 10 Hz,increased the dislocation density of the material,and promoted the penetration of corrosive media.It also accelerated the corrosion process,and resulted in a 15.13%decrease of the material corrosion fatigue life.

关 键 词：盐雾腐蚀疲劳 6061-T6铝合金 微观形貌表征 加载频率 

分 类 号：TB31[一般工业技术—材料科学与工程]