Study of beam wobbling technique and porosity formation in laser welding of ultra-thin AA1050 sheet-microstructural and mechanical analysis

The fabrication of lightweight components has been at the forefront of technological advancements in present-day electrical vehicle components. However, the use of ultra-thin AA1050 sheet materials for critical battery components, such as cooling plates, remains a challenge due to the need for adequate joining techniques. This paper investigated the reliability of joining these sheets using laser welding with the wobbling technique. The primary aim was to understand the effect of wobbling on the porosity formation and investigation of the weld properties and morphology. In this regard, response surface methodology (RSM) was used to optimise the laser welding process parameters and to maximise the responses in terms of lap shear strength, interface width and area (%) of porosities present in the joint. The analysis of variance was used to obtain a set of optimised input parameters affecting the strength and morphology of the weld, and these were welding speed of 2000 mm/min, laser power of 300 W, and wobbling amplitude of 0.6 mm. Furthermore, the use of the wobbling technique resulted in uniform distribution of heat input thereby leading to the refinement of the equiaxed grains and augmented the weld's microhardness. A comprehensive analysis of the effect of wobbling on the porosity formation in joining the ultra-thin sheets was presented for a better understanding.