2219铝合金焊接接头晶间腐蚀行为

采用晶间腐蚀试验及极化曲线测试方法对2219铝合金母材、搅拌摩擦焊（FSW）及钨极氩弧焊（TIG）接头的腐蚀行为进行分析，借助金相显微镜、激光共聚焦显微镜、体视显微镜、扫描电镜及能谱仪分析腐蚀形貌及腐蚀产物.结果表明，2219铝合金母材及焊接接头的腐蚀行为主要与析出相有关，Al₂Cu的析出导致贫铜的无沉淀带作为阳极优先溶解.母材的抗晶间腐蚀能力最差，由表面点蚀开始，沿轧制方向逐渐发展为剥落腐蚀；TIG焊次之，表现为网状晶间腐蚀；FSW焊最低，焊核表现为点蚀，散落分布于表面.

Intergranular corrosion behavior of 2219 aluminum alloy's welding join

The corrosion behavior of 2219 aluminum alloy and its welding joints (made by FSW and TIG welding) were investigated through intergranular corrosion test and polarization curve measurement. Metalloscope, laser scanning confocal microscope and scanning electron microscopy were employed to analyze the corrosion morphology, and corrosion products were measured by energy spectrometer. The results show that the corrosion behavior of 2219 aluminum alloy and its welding joints are related to precipitated phase, and the precipitation of Al₂Cu phase leads to the dissolution of poor Cu zone as the anode. The base metal shows the worst corrosion resistance ability, whose pitting corrosion develops to exfoliation corrosion along the rolling direction in corrosion media (NaCl+H₂O₂). The corrosion resistance of FSW joint is superior to that of TIG joint. TIG joint shows intergranular corrosion with network cracks, and FSW joint shows corrosion pits distributing scatteringly on the surface.