Hot Extrusion Processing of Al–Li Alloy Profiles and Related Issues: A Review

Abstract

Al–Li alloy is a new structural material with the advantages of lightweight and high strength. The extrusion profiles of Al–Li alloy are widely used in aerospace and other fields, which can significantly reduce the weight of the aerospace equipment and improve their carrying capacity and service performance. Particular service conditions of structural components in aeronautical and space areas put forward strict requirements on microstructure, mechanical properties, and dimensional precision of Al–Li alloy profiles. Therefore, it places higher requirements on the shape forming and microstructure controlling of the Al–Li alloy profiles. The manufacturing process of the profiles involves billet homogenization, hot extrusion, solution and quenching treatments, artificial aging, and others. The parameters of each process as well as the die structure have important effects on the final performance of the profiles. This article summarizes the main applications and key mechanical properties of Al–Li alloy extrusion profiles. The technologies related to the manufacturing process of the extrusion profiles are summarized and analyzed. The related studies about the evolutions of the microstructure and mechanical properties during homogenization and extrusion processes are reviewed. The developments of the solid solution and quenching treatments as well as the aging strengthening technology for extruded Al–Li alloy profiles are also introduced. The scientific problems and key technologies that need to be solved in the manufacturing of Al–Li alloy extrusion profiles are presented, and the prospect for future development trends in these fields is given.