Microstructural characteristics and mechanical properties of dissimilar AA5052-H32 and AA5083-H111 alloy joints made using tungsten inert gas welding and ER5356/scandium composite cast filler rod

Abstract

In this research, casted filler rod with combination of ER5356 and scandium (Sc) composites are subjected to conduct the Tungsten Inert Gas (TIG) welding on AA5052-H32 and AA5083-H111 was investigated. The mechanical properties and microstructure of the TIG welded dissimilar joints were analysed. The responses like tensile and microhardness were improved on TIG welded joints with appropriated process parameters and fusion zone enhanced with defect free joints through the microstructure.The composed filler rod is newer technique to achieve the good quality welding which was more dependable and very flexible in different sectors of engineering applications. The following parameters like ER5356, ER5356 with 0.25% and 0.50% scandium filler rods are used to conduct the TIG welding with specified parameters of current at 150 A and gas flow rate at 12 L/min. The tensile strength of dissimilar TIG welded joints were increased 60.6%–86.7% of the Al–Mg alloy base metal. The enhanced mechanical strength was attained to the creation of scandium made ER 5356 filler rods dispersed that successfully restrict the grain growth in boundary regions and recrystallization of the fusion zone. The microhardness of the Tig welded joint made with ER 5356 with 0.255 and 0.50% improves the hardness (88 and 110 Hv) than the no scandium added TIG welded joint hardness (68 Hv). This enhancement in mechanical properties is associated with modifications in microstructure and the progression of strengthening phases precipitation.

Keywords

• Scandium
• ER5356
• TIG
• Mechanical properties and SEM