A study on cracks and IMCs in laser welding of Al and Cu

Aluminum-copper laser welding has become a crucial joining technology for battery manufacturing. However, dissimilar material mixing in welding often causes the formation of intermetallic compounds (IMCs) and cracks, which reduce weld quality. In this study, the effects of laser power and welding speed on material mixing, IMCs formations, and crack formation were investigated by 3D micro-X-ray computed tomography imaging, computational fluid dynamics, and chemical/elemental analyses. Of crack formation during Al-Cu laser welding, transverse cracking was found to be the major type. The crack formation is associated with the IMC distributions generated throughout the weld fusion zone when high laser energy input caused more extensive Al/Cu material mixing.