Formability Analysis of Dissimilar Aluminium Tailor Welded Blanks by Low-Powered Fibre Laser for Lightweight Automotive Application

The automotive industry is increasingly adopting lightweight materials to improve fuel efficiency and reduce emissions, with aluminium alloys emerging as a promising option for vehicle weight reduction. This study investigates the formability challenges of dissimilar AA5052-H32 and AA6061-T6 aluminium tailor welded blanks (TWBs) fabricated using low-powered fibre laser welding for potential lightweight automotive applications. Welding parameters included laser powers of 270 W, 290 W and 310 W, paired with welding speeds of 10 mm/s, 15 mm/s and 20 mm/s, to join the dissimilar alloy pair in a butt-weld configuration via successive double-sided welding. Limiting dome height (LDH) tests revealed that the TWBs achieved only 35-40% of base metal formability, with fracture strains below 0.1 for both major and minor deformations. The presence of porosity in the weld zone, including a softening region identified by microhardness testing, contributed to premature failure during formability testing. These findings highlight the challenges associated with forming operations involving low-power laser welded aluminium TWBs and necessitate further research to improve formability and address manufacturing constraints.