Intergranular corrosion effect on fatigue behavior of dissimilar 6005A‐5083 aluminum alloys weld joints

Abstract

AbstractThe effects of the intergranular corrosion (IGC) defect depth on the high circle fatigue performance of tungsten inert gas (TIG)‐welded joints of 6005A–5083 dissimilar aluminum alloys were investigated. After soaking in different IGC solutions for 72 h, corrosion defects of different depths were generated in various areas of the specimen surfaces. It was found that the 5083 base metal exhibited the poorest corrosion resistance, while the welded metal displayed the best corrosion resistance. Fatigue tests carried out after precorrosion revealed that when the IGC depth was shallow, the weld defects on the weld metal were the main source of cracking for fatigue extension. However, when the IGC depth in the 5083 base metal was >248 μm, the corrosion defect acted as the origin of the fatigue crack, and the fatigue life of the sample was significantly reduced. This was attributed mainly to the local high‐stress field at the tip of the corrosion defect. Finally, a corrosion fatigue crack expansion model was established to analyze the influence of the corrosion defect depth on the fatigue lives of welded joints.