摘要
对42 mm厚6082-T6铝合金进行双面搅拌摩擦焊接,采用晶间腐蚀试验研究了接头分层试样的晶间腐蚀行为,结合接头微观组织、显微硬度和微区析出相特征,分析了影响接头微区晶间腐蚀行为的关键因素。研究结果表明,上、下表层焊核区为细小的等轴晶组织,搭接的焊核区经过双重搅拌作用,晶粒更为细小。接头表层和中心层的显微硬度分别呈W型和V型分布,接头的腐蚀程度与显微硬度没有对应关系。接头各层的母材和HAZ2均发生严重的晶间腐蚀,而其他微区未发现明显的晶间腐蚀现象。母材区晶内析出相与沉淀无析出带之间的电位差和HAZ2区晶界上的富Cu相粒子是导致晶间腐蚀敏感性较大的根本原因。
The double-side friction stir welding is used for a 42 mm thick 6082-T6 aluminum alloy.The intergranular corrosion behavior of joints delamination specimen is studied by intergranular corrosion test.Based on the microstructure,microhardness and precipitate characteristics of the joint,the key factors affecting the intergranular corrosion behavior of the joint microdomain are analyzed.The results show that the weld nugget zones of the top and bottom layers are small equiaxed crystal structures,and under the action of double stir,the grains of the lapped weld nugget zone are finer.The microhardness distributions of the surface layer and the middle layer of the joint are W-shaped and V-shaped,respectively,and the corrosion degree of the joint does not correspond to the microhardness.Serious intergranular corrosion occurs in the base metal and HAZ2 of each layer of the joint,while no obvious intergranular corrosion is observed in other microdomains.The potential difference between the precipitates and the precipitate free zone in the base material zone and the Cu-rich phase particles on the grain boundary of the HAZ2 zone are the main reasons for the high sensitivity of the intergranular corrosion.
作者
孙大森
张志强
凌晨
何长树
SUN Dasen;ZHANG Zhiqiang;LING Chen;HE Changshu(Qingdao Rolling Stock Supervision Project Department,China Railway Ji'nan Bureau Group Co.,Ltd.,Qingdao 266111,China;School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;Key Laboratory for Anisotropy and Texture of Materials,Northeastern University,Shenyang 110819,China)
出处
《电焊机》
2019年第11期58-64,共7页
Electric Welding Machine
基金
国家重点研发计划(2016YFB1200506-12)
