Optical strain measurements during pulsed laser beam welding to improve the understanding of hot crack formation of EN AW-6082 aluminum alloy

E-mobility turned in the last years to be an emerging market and one solution to fossil fuel free mobility for the future. E-mobility requires, compared to fossil-fueled mobility concepts, a huge amount of welding tasks, which have to guarantee different functionality, as for example high strength, ductility, but also low resistivity and tightness. Last is especially for housing or cases of aluminum in automotive challenging, as pores and cracks can occur. Pulsed laser welding presents, due to the adaptable heat input and the temporal modification of stress state and solidification conditions advantages for this type of applications. EN AW-6xxx group of aluminum alloys is mainly used for such components due to their favorable mechanical properties. However, these alloys are susceptible to hot cracking during solidification from the molten phase. This article aims to present a methodology for demonstrating the resulting strain during pulsed laser beam welding of hot crack susceptible aluminum alloys. It will highlight the influence of factors such as pulse shape, shielding gas, and flow rate on strain and strain rate.