Weldability improvement by wobbling technique in high power density laser welding of two aluminum alloys: Al-5052 and Al-6061

This paper presents a new approach in laser welding of Al-5052 and heat Al-6061 aluminum alloys, which are challenging materials for a good laser welding quality. The process consists of applying very small size of 0.1 mm to provide a high density of power that aims at imposing a high amount of heat that is required for aluminum alloys; simultaneously the wobbling technique is implemented to reduce the risk of overheating in the welding area. Having relied on the capability of the wobbling technique to distribute the generated heat, welding results contained negligible thermal defects compared to the usual defects such as underfill, undercut, and root reinforcement. The resulted welding zones show a fully penetrated welding quality for both alloys with a smooth weld seam at the top and root surface. Analysis indicates a higher tensile strength of 190 MPa for Al-5052 corresponding to an 18% decrease from the base metal, while this reduction of mechanical strength in the welded zone for Al-6061 was about 27%. Also, the hardness profile of Al-5052 reveals a small reduction in the fusion zone in contrast to Al-6061, for which a high hardness decrease happens in the welded zone. This approach is more profitable for the cost-effectiveness of the process since the laser power is set at a low range as the high-power density is mainly related to the small size of the spot diameter.