Progress in Laser Beam Welding of High-strength Aluminum-lithium Alloys

Aluminum-lithium (Al-Li) alloys are considered as the most prospective light-weight structural materials for applications in the aerospace industry. Laser beam welding is a distinct candidate process to join aluminum structures with high quality and efficiency. Al-Li alloys tend to be more susceptible to hydrogen porosity than conventional Al alloys and keyhole porosity in welds is formed when the laser welding is unstable. Hot cracking is commonly encountered, which is associated with alloying elements and solidification process. Mechanical property degradation of laser welded joints is affected by weld microstructure, joint appearance and weld defects in Al-Li alloys. This paper covers the state-of-art of laser beam welding of Al-Li alloys, highlighting the generation and prevention of weld porosity and hot cracking, the joint microstructures and mechanical properties. Finally, recent progress in T-joint welding of newly developed Al-Li alloys 2060- T8 and 2099- T83 with two high brightness lasers for aircraft fuselage applications is demonstrated.