Resistance spot weldability of heat-treatable and non-heat-treatable dissimilar aluminium alloys

This study addresses issues relevant to resistance spot welding of AA5xxx and AA6xxx dissimilar aluminium alloys. Welding parameters are optimised to provide the maximum lap-shear strength and the largest nugget size. As mechanical properties of the weld are affected by the characteristics of the heat-affected zone as well as the fusion zone, microscopic analysis was performed to address the weld microstructure and the mechanical performance. The asymmetrical nugget morphology and heterogeneous properties of the weld are due to the distinctive physical properties and strengthening mechanisms of the welded materials. The welding current range for the dissimilar pair falls between those for the similar combinations. A computational analysis using SORPAS is performed to address the resulted microstructure from welding.