The Effect of Pre-Strain and Solution Heat Treatment on the Formability of a 2024 Aluminium Alloy
- 257 Downloads
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.
Key wordsAluminium 2024 Solution Heat Treating Formability Stretch Forming
Unable to display preview. Download preview PDF.
- 1.M. O’Donnell, Finite Element Modelling of a Multi-Stage Stretch-Forming Operation using Aerospace Alloys, PhD Thesis, University of Ulster (2003).Google Scholar
- 2.E. N. Straatsma, L. Velterop, Influence of Heat Treatments and Straining Steps on Mechanical Properties in the Stretch Forming Process, in Proc. 9th Int. Conf. on Aluminium Alloys, 2004, 771–776.Google Scholar
- 3.J. R. Davis, Alloy and Temper Designation Systems, in Aluminium and Aluminium Alloys, ASM International, (1993), 29.Google Scholar
- 4.O.-G. Lademo, O. S. Hopperstad, M, Langseth, An Evaluation of Yield Criteria and Flow Rules for Aluminium Alloys International Journal of Plasticity, 15, (2), (1999), 191–208.Google Scholar
- 5.M. O’Donnell, D. Banabic, A. G. Leacock, D. Brown, R. J. McMurray, The Effect of Pre-Strain and Inter-Stage Annealing on the Formability of a 2024 Aluminium Alloy, in Proc. 11th ESAFORM, (2008).Google Scholar
- 6.U. Koster, Recrystallization involving a second phase, Metal Science, 8, (5), (1974) 151–60.Google Scholar
- 7.R.D. Doherty, D. A. Hughes, F. J. Humphreys, J.J. Jonas, D. J. Jensen, M. E. Kassner, W. E. King, T. R. McNelley, H. J. McQueen, A. D. Rollett, Current Issues in Recrystallization: a Review, Materials Science & Engineering A, A238, (2), (1997), 219–74.Google Scholar
- 8.F. J. Humphreys, The Nucleation of Recrystallization at Second Phase Particles in Deformed Aluminium, Acta Metallurgica, 25 (1977), 1323–1344.Google Scholar
- 9.W. Wen, J. G. Morris, An investigation of serrated yielding in 5000 series aluminium, Materials Science and Engineering A, 354, (2003), 279–285.Google Scholar