Microstructure – mechanical properties correlation in ER5356-assisted fiber laser welding of thin AA5754 sheets

Studies pertaining to the correlation between weld parameters, mechanical properties, and microstructure of thin AA5754 alloy sheets using ER5356 filler wire in fiber laser welding are scarce. Therefore, the present study investigates the influence of process parameters on the fiber laser welding of thin AA5754 sheets using ER5356 filler wire in butt joint configuration. Laser welding was performed using Taguchi L9 design of experiments to investigate the effects of laser power, wobble frequency, and speed on welded joints. Sound weld quality with the tensile strength equivalent to the base metal was achieved. Bend test revealed no visible crack formation confirming the ductile nature and soundness of the welded joint. A W-shape axisymmetric Vickers microhardness profile was observed with lowest hardness values observed in heat affected zone or weld metal region. EDS (Energy dispersive X-ray spectroscopy) analysis confirmed the increase of magnesium content in the weld zone with the addition of filler wire, while EDS line scan indicated Mg 2 Si (magnesium silicide) segregation near aluminium grain boundaries in the heat affected zone. This study provides useful insights for weld-assisted fabrication of thin AA5754 alloy lightweight components in automotive, marine, construction, and transportation sectors.