Effects of heat input and different types of welding current on the microstructure and mechanical properties of TIG weld joints of a modified Al-Mg-Si cast aluminum alloy

The effect of heat input (HI) on the microstructures and mechanical properties of TIG weld joints of Al-Mg-Si alloys was investigated. The influences of continuous and pulse welding currents on the microstructures and hardness behavior of the alloys were also studied. The amount of HI was controlled by variation in the welding velocity. The filler metal used through welding was ER4043 Al-5%Si. The micrographs of optical and scanning electron microscopes revealed that as the type of imposed current changed from continuous to pulse current, the amount of HI decreased and, consequently, the mechanical properties of the weld joints improved. Furthermore, the results showed that the use of pulse current could contribute to grain refinement and a decrease in the width of heat affected zone (HAZ).