Understanding novel gap-bridged remote laser welded (RLW) joints for automotive high-rate and temperature applications

This paper investigates the microstructure, high-rate and temperature dependent tensile behaviour of fillet edge joints produced by novel ‘gap-bridged’ remote laser welding (RLW) using an automotive grade aluminium alloy AA6014, commercially known as AC-170PX, extensively used for skin panel applications. Three part-to-part gap-bridged RLW welds, with different gaps (0.2 mm, 0.4 mm 0.6 mm) were examined joint geometry microstructure. Relatively larger columnar grains resulting from directional solidification observed in fusion zone microhardness was reduced ~15- 20% due to precipitates disappearance. Moderate (0.1 m/s) high speed rate (10 tests performed at room (~23°C) determine performance. Although strain dependency found be low, increase extension obtained. Additionally, performance evaluated over a range temperatures between -50°C 300°C. Using digital image correlation (DIC), fracture strains obtained 0.21 0.25 all gap conditions. Fusion based finite element simulations Johnson-Cook material failure model predict strength. suitability applications determined comparison two industrial joining methods, self-piercing riveting (SPR) resistance spot (RSW).