Cu含量对2219铝合金锻件及其焊接接头组织与性能的影响

Effect of Cu Content on Microstructure and Properties of 2219 Aluminum Alloy Forgings and Its Welded Joints

采用力学拉伸实验、焊接实验、电化学阻抗谱(EIS)、循环阳极极化曲线(Tafel)以及金相和扫描电镜(SEM)等分析测试方法,研究Cu含量对2219铝合金锻件组织与性能的影响。结果表明:降低Cu含量,有利于减少2219铝合金基体内的残余结晶相,并有效抑制在合金焊接过程中粗大Al_2Cu相的析出,使基材和焊件的伸长率显著提高,强度略有下降;Cu在铝基体中形成Al_2Cu相诱导合金发生局部腐蚀,使材料的耐腐蚀性能变差,降低Cu含量能够减小合金的腐蚀倾向,改善合金的耐腐蚀性能。

The influence of Cu content on microstructure and properties of 2219 aluminum alloy was investigated by using tensile tests, welding tests, electrochemical impedance spectroscopy （EIS） , cyclic anodic polarization curves （Tafel） combined with optical micros-copy （OM） and scanning electron microscopy analysis （ SEM）. The results indicate that the residual crystal phase in the matrix of 2219 aluminum alloy is reduced with the decrease of Cu content which contributed to effectively suppress the precipitation of Al2Cu coarse phase during the welding process. Furthermore, with the decrease of Cu content, elongation of the alloy is significantly in-creased ,while the tensile strength and yield strength is slightly decreased. At the same time, Al2 Cu phase formed in the matrix induces localized corrosion which causes the deterioration of corrosion resistance in the alloy, while the corrosion tendency of the alloy can be reduced by the decrease of Cu content and the corrosion resistance of the alloy is improved.