摘要
目的研究7B04铝合金硫酸阳极化层环境作用下的失效行为,分析单独盐雾试验和环境谱作用下阳极化层的损伤行为和影响因素。方法通过中性盐雾试验和环境谱周期性试验(盐雾试验+温度试验)研究了硫酸阳极化层在不同腐蚀时间或不同腐蚀周期下的腐蚀损伤变化过程,并采用体视显微镜和扫描电子显微镜(SEM)观察了不同腐蚀时间下或不同腐蚀周期下的表面形貌,结合有限元方法研究了阳极化层与铝合金基体热膨胀系数不匹配引起的热应力,定量分析了热应力对阳极化层失效行为的影响。结果经历中性盐雾试验和环境谱试验的硫酸阳极化层损伤失效现象是不一样的,中性盐雾试验中硫酸阳极化层主要呈鼓起开裂失效,而环境谱试验中硫酸阳极化层以开裂剥落失效为主。结论中性盐雾试验中硫酸阳极化层主要是腐蚀介质通过表面微孔进入基体,导致基体腐蚀阳极化层鼓起,而环境谱试验因温度作用产生的热应力引起了硫酸阳极化层的开裂,形成了腐蚀介质进入基体的通道,引起阳极化层的剥落。
Objective To research failure behaviors of anodic films on aluminum alloy in corrosion environment and analyze damage behaviors and influential factors of anodic films under separate salt spray test and environmental spectra test. Methods The changing process of corrosion damage on sulfuric acid anodic film in different corrosion states and periods was researched through neutral salt spray test and environmental periodic test （salt spray test and temperature test）. Surface morphologies were observed by stereoscopic microscope and scanning electron microscopy （SEM） at different time or corrosion cycle, and finite element method （FEM） was used to research the thermal stress due to the coefficient of thermal expansion of aluminum alloy matrix and anodic film. Results Damage failures of sulfuric acid anodic films after neutral salt spray test and environmental spectra test were different. The failure of sulfuric acid anodic film after neutral salt spray test was bugling crack, which was different from the main failure of peeling off cracking on anodic films after test. Canclusion In neutral salt spray test, corrosive comes into the matrix of the sulfuric acid anodic film and resultsin plumping of the anodic film. While in the environment spectrum test, the thermal stress generated for high temperature causes cracking of the sulfuric acid anodic film and forms a channel through which corrosive medium can enter the substrate to cause peeling off of anodic film.
出处
《装备环境工程》
CAS
2017年第3期123-127,共5页
Equipment Environmental Engineering
关键词
铝合金
阳极化层
腐蚀
热应力
有限元
aluminum alloy
anodic film
corrosion
thermal stress
FEM
