Prospects for using aluminium-lithium alloys for stamped-welded aviation structures

The majority of aviation structures (sections, fuel tanks, pilot's cabin, central section, tail, etc.) extend to the aerodynamic surface and, consequently, have a complicated form of double or double sign-changing curvature. Two technological approaches are being developed and improved for the process of assembling and welding such volume structures: frame-panel and panel. In this work, the authors propose a basic technology of producing large panel welded structures for aircraft (module finned panels of the required curvature) on the basis of combining the processes of welding and shaping in the superplasticity condition of the metal. In this case, the optimum structure of the material are alloys based on titanium and aluminium with satisfactory weldability. In particular, in the group of Al alloys this refers to alloys alloyed with lithium and having high specific parameters of strength and stiffness, so that they are highly promising for producing aircraft structures. Materials: 1420, 1420RS and 1423 aluminum base alloys.