A study on the effect of pulsed current gas tungsten arc welding parameters on the microstructural evolutions, corrosion behavior and mechanical properties of AA 5456 weld joints

Nowadays, aluminum and its alloys have extensive applications in marine and aerospace industrious owing to their excellent properties. Among these alloys, 5xxx series of aluminum alloys have also excellent corrosion resistance, high toughness and strength and also good weldability. Decrease in yield strength and also tensile strength due to the grain growth in the heat affected zone is of the main problems in the welding of these series of Al alloys. In this research work, gas tungsten arc weld joints in two modes i. e. direct current and pulsed current were compared in order to study the effect of this parameter on the microstructure, mechanical properties and corrosion resistance of weld joints. Also, the effect pulsed current parameters such as peak current and basic current were investigated. Microstructural evolutions and fracture surfaces of weld joints were examined by optical microscope and scanning electron microscope, respectively. It was found that the fracture behavior of all joints is in a ductile manner. Also, tensile test and electrochemical polarization were conducted in order to study the mechanical properties and corrosion behavior of weld joints.