Microstructural study in AA7075 alloys welded with different filler metals

Even though AA 7075 is an aluminum alloy with high mechanical properties, it is not often applied in manufacturing. This is so, because it is considered as very difficult to produce defect free welded joints. This is so, because this alloy has a tendency to hot cracking. The metallurgical problems that appear during welding of AA 7075 have not been fully solved but they have been reduced by applying alloys such as: 4043 and 5356 as filler metals. However, in literature there is little information about the metallurgical effects of these types of filler metals applied in arc welded joints of AA7075. This is especially true for Tungsten Inert gas welding. Therefore, this work is focused in comparing the microstructure and Vickers microhardness in weldments of AA 7075 with ER4043, ER5356 and AA7075 as filler metals. Besides, a set of welded joints with the three different filler metals were quenched after welding in order to modify the final microstructure. The results were evaluated by microstructural analysis focused on the Heat Affected Zone and Vickers microhardness and they were compared among them.