Effect of Pulse Current on Mechanical, Metallurgical and Corrosion Properties of AA 5083 Aluminum Alloy Pulse TIG Welded Joints

Aluminum alloys are largely used because of their inherent good properties. Nowadays, 5xxx series alloys are developed and one of their new categories is Al-4.5Mg. High strength in this alloy is due to work hardening. It has ultimate tensile strength of 330 MPa. The most important challenge during fusion welding of this alloy is HAZ softening. The aim ofthe present investigation is to study the effect of pulse current on mechanical and metallurgical properties of AA5083 aluminum alloy welds through pulsed tungsten inert gas (TIG) welding process. Microstructures of all the welds were studied and correlated with the mechanical properties. It was seemed that pulse current, has an optimum amount to reach the highest strength. All the welded specimens were failed within theweld region. Pulsed welds showed fine grain structure due to thermal disturbances and decrease in heat input. In general, hardness is lower in HAZ region compared to the weld metal and base metal regions, irrespective of welding technique, which is characterized by the coarse dendrite grains and lack of the strengthener phase. Hardness was highercompared to the continuous welds and this could be due to refinement of grain structure. The best peak current should be selected between 220 & 240 A.