材料期刊网

采用微型电池(Microcell)和浸泡腐蚀试验研究了2219-O铝合金搅拌摩擦焊接接头在0.5 mol/L NaCl中性溶液中的微区电化学特征和腐蚀行为,通过光学轮廓仪分析了经14 d浸泡后接头的均匀腐蚀深度以及点蚀形貌、深度和密度,讨论了影响腐蚀行为的机理.结果表明:接头在无外电流干扰下即发生点蚀.与母材相比,热影响区的腐蚀行为没有明显改变;热机械影响区的耐蚀性略有提高;轴肩作用区(SAZ)因θ相回溶和被打碎,提高了基体中固溶的Cu含量,降低了SAZ的腐蚀速率以及点蚀深度、体积和密度,耐蚀性提高.

The micro-electrochemical characteristics and corrosion behavior of a friction stir welded AA2219-O joint in 0.5 mol/L NaCl neutral solution were characterized using a microcell method and immersion test,respectively.An optical profilometer was employed to analyze the uniform corrosion depth as well as the pitting corrosion morphology,depth and density of the joint after being immersed for 14 days.The mechanism which affected the corrosion behavior was discussed.The results showed that pitting corrosion occurred without applied potential.Compared to the base metal,the corrosion resistance was similar in the heat affected zone,slightly improved in the thermomechanically affected zone.In the shoulder affected zone (SAZ),the θ phase particles were partly dissolved and broken,which led to an increase in the content of dissolved Cu in the matrix,and decreased the weight-loss corrosion rate as well as the pitting depth,volume and density.As a result,the corrosion resistance significantly increased in the SAZ.