高强铝锂合金激光焊接研究进展

铝锂合金被认为是一种很有发展前途的航空航天轻质结构材料,而激光焊接是实现铝合金结构优质、高效连接的一种先进方法.铝锂合金比常规铝合金具有更高的氢气孔敏感性,焊接时极易产生氢气孔;进行激光深熔焊接时,焊接过程的不稳定也可能导致小孔型气孔产生.铝锂合金属焊接时也存在焊接热裂纹问题,这主要与合金元素及焊接凝固过程有关.接头显微组织、焊接成形及焊接缺陷的存在均会影响接头的力学性能.介绍了铝锂合金激光焊接现状,重点讨论了铝锂合金激光焊接过程中气孔和裂纹的产生与防止、焊接接头的显微组织和力学性能.最后,介绍了2060-T8和2099-T83新型高强铝锂合金T型接头双光束高亮度固体激光焊接的最新进展.

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.