Advances in Defect Analysis and Performance of Laser-Metal Inert Gas Hybrid Welded Aluminum Alloy Joints

Hybrid welding, using the combination of a laser and a MIG arc, is designed to overcome problems commonly encountered during either laser or MIG welding, such as cracking and porosity. Laser welding has gained a reputation due to its ability to produce narrow and deep weld pool, but it is also very difficult for highly reflective materials like aluminum. Hybrid welding can efficiently weld the materials having high reflectivity, allowing increased gap tolerances, as compared to laser welding, while retaining the high weld speed and penetration necessary for the efficient welding of thicker workpieces. Despite the growing interest, there is a lack of comprehensive summaries on the laser-MIG hybrid welding of aluminum alloys. This study employs a bibliometric analysis using VOSviewer to evaluate literature from the Web of Science core database covering 2000 to 2023. The study identifies five primary research hotspots: the interaction of laser and MIG welding, optimization of process parameters and joint properties, softening of the heat-affected zone, the relationship between microstructure and mechanical properties, and control of welding residual stresses and distortion. An important observation from the analysis is that the coupling effect between hybrid plasma and melt pool is critical in forming welding defects, highlighting the need for further investigation to optimize defect mitigation strategies. Moreover, advancing theoretical studies and numerical simulations of the laser-MIG arc plasma interaction are imperative for the continued development of hybrid welding applications. Promising approaches for monitoring and optimizing defects like porosity and cracking include integrating machine learning and digital twin technologies. This review systematically evaluates current progress in addressing key issues, investigates causes and mechanisms of defects for improving joint performance, and outlines future challenges in laser-MIG hybrid welding of aluminum alloys, serving as a valuable reference for enhancing performance and fostering the application of this welding technique.