The Effect of Pre-Strain and Solution Heat Treatment on the Formability of a 2024 Aluminium Alloy

摘要

The double curvatures encountered in aerospace skin components require significant plastic strain levels to achieve final form. In order to obtain the required part geometry and final temper strength, while avoiding failure, multistage-processing is employed. For components that are more difficult to form this requires three stretching stages and two heat treatment processes. After the first forming stage the material is annealed, then formed to a second strain level, before solution heat treatment and final form. An experiment that replicates this processing route is presented. The results indicate that for all processing routes the material exhibits a significant change in texture as described by the r-values. Furthermore, the biggest strength increase is obtained when using the lowest total strain processing route. The formability of the processed material is shown to be less than the original fully annealed sheet, although there is little difference in the formability of the various processing routes.