Effect of Filler-wire on Corrosion Resistance of Some 5000 Al Weldments

摘要

Considering the experimental results obtained in this investigation, the following conclusions could be submitted. Aluminium alloy 5052-H12 has a better resistance to localized corrosion than 5083-0 Aluminium alloy. This was attributed to the presence of the highly anodic beta phase (Mg_2Al_3) in the latter. Weld joints of 5083-0 Al alloy with 5183 and 5356 Al filler-wires have shown localized-corrosion comparable to that of autogeneous weld of the base-metal, which was related to a matching composition of the joints. Using filler wire 4043 Al has resulted in a increase in localized corrosion of the weld joint due to the presence of insoluble excess silicon. Iron and copper also have a contributing effect. Localized corrosion of 5052-H12 Al alloy with 5183 and 5356 Al filler-wires has largely increased due to the formation of (3 phase (Mg_2Al_3) in the weldzone. weld joint "5052-H12/4043 has shown a reasonable increase in localized corrosion, which could be attributed to an eventual formation of Mg_2Si, having a corrosion potential very close to the matrix. Hardness profile was almost constant in the weld joints of 5083-0/5000 Al filler- wires, whereas a drop of hardness in the weld zone and heat -affected zone of the work-hardened joints 5052-H12/5000 Al was obtained. On using Al-Si filler-wire (4043 Al) with either base-metal alloys, an in crease in hardness was observed in the weld-zone, which was related to the formation of Mg_2Si.