Continuous laser welding with spatial beam oscillation of dissimilar thin sheet materials (Al-Cu and Cu-Al): Process optimization and characterization

Continuous laser welding with spatial beam oscillation was investigated as a method of joining combinations of thin copper and aluminum sheets. Welding of these materials is required for manufacturing of electronic components due to their physical properties. Welding of dissimilar metals such as Al-Cu with conventional manufacturing techniques is difficult due to unavoidable formation of brittle intermetallic compounds, which reduce both the mechanical and electrical properties of the joint. The aim of this work was to understand how process parameters such as laser power, welding speed and wobbling amplitude affected the weld seam, making it possible to determine which parameters were of greatest influence on the mechanical and electrical properties of the resulting joint. Both the width and penetration of the weld seam were strongly correlated to the wobbling amplitude. The ultimate tensile strength of both configurations (Al-Cu and Cu-Al) was as high as 100 kgf with optimized process parameters. Micro-hardness tests showed an increase in hardness near the molten area. The temperatures attained during welding were approximately 40 degrees C at 10 mm from the weld seam. Low electrical contact resistance and high tensile strengths were obtained with the same parameters.