Investigation of the microstructure and mechanical properties of AA5049 aluminum alloy joined by laser welding

Laser welding is a precise and efficient joining technology commonly used for aluminum alloys, which are known for their high reflectivity and thermal conductivity. Owing to its limited heat input, it creates a narrow heat-affected zone (HAZ), thus reducing distortion and improving dimensional stability. In this thesis study, 3 mm thick AA5049 aluminum alloy plates were joined using laser welding, and the effects of various welding parameters on the microstructural and mechanical properties of the fusion zone were experimentally investigated. Three main welding parameters laser power, welding speed, and wobble frequency were varied, resulting in a total of 18 different welded samples. For each sample, tensile testing, three-point bending tests, microhardness measurements, optical microscopy, SEM (Scanning Electron Microscopy), and EDX (Energy Dispersive X-ray Spectroscopy) analyses were conducted. The results demonstrated that welding parameters have a significant effect on microstructure formation and mechanical performance. The influence of parameter variations was particularly evident in the hardness distribution and microstructural transitions. At the end of the study, the characteristic behavior of the fusion zones produced by laser welding of AA5049 aluminum alloy was revealed.