Effect of Silicon Content in Al–Si Welding Wire on Mechanical Properties of Al/Cu Laser Welded Joint

In this study, the laser welding of Al/Cu using Al–Si welding wires was analyzed. The impact of varying silicon content in the Al–Si welding wires (0%, 12%, 16%, 20%) and laser power settings ranging from 900 to 1050W in 50W increments on the phase composition, microstructure, and mechanical properties of the weld joints was investigated. It was observed that a silicon-rich interface layer formed near the copper side of the weld seam. This formation led to grain orientation and a significant reduction in grain size. As the Si content increased, the morphological structure transformed from irregularly layered dendritic to regularly oriented dendritic, and ultimately to equiaxed crystals. X-ray diffraction analysis of the weld seam revealed the presence of main intermetallic phases, including Al2Cu. It was concluded that the highest tensile strength, reaching 85.1 MPa, was achieved using an AlSi12 weld filler at a power of 900W.