High Strength Aluminium Alloys Extrusions - A Review of the Thermo-Mechanical-Process in High Performance Profile Manufacturing

Abstract:

High strength aluminium alloys extrusions have successfully been applied for years in transportation industry. High strength alloys are normally understood to be alloys based on the Al-Mg-Zn system (7xxx) with addition of Cu in some cases and of course some micro structural controlling elements as Cr or Zr. The level of strength in the hardened condition (T6) is typical in the range from 320 to 500 MPa. The combination of strength and ductility of extrusions from the 7xxx series alloy gives several advantages in light weight construction and can contribute to lighter body and chassis in automotive. Significant improvements in extrusion speed are realized when the ratio Zn/Mg is increasing this means that alloys with high Zn and low Mg like 7108 and 7003 are favourable. Zr is the most promising element with respect to control the recrystallization phenomena. The fully understanding chemistry and the thermo-mechanical process route in profile based components manufacturing is concluded to be fundamental for high performance products.

• Periodical: Key Engineering Materials (Volume 491)
• Pages: 11-18
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.491.11
• Online since: September 2011
• Authors: Ola Jensrud
• Keywords: Extrudability, High Strength Alloys, Mechanical Property

References

[1] Kurt Laue and Helmut Stenger, EXTRUSION, American Society for Metals (1981).

[2] K. Asbøll and O. Jenrud, Int. conf. Of Light Metal in the Automotive Industry, Part 18. Materials and Process Development for the Cost Effective Production of Structural Aluminium Components, Lillehammer 14. – 16. June 1994. Ministry of Industry and Energy Conference Proceedings.

[3] K. Asbøll, O. Jensrud, D. Jacobsen and O. Reiso, Extrudability and Mechanical Properties of some 7XXX – series Alloys, Conference Proceedings of ET 96 (1996).

[4] B. Rønning, Constitutive relationship for AlZnMg, AlZnMgCr and AlZnMgZr alloys, PhD Thesis at NTNU (1998).

[5] O. Jensrud and T. Løken. The extrudability of medium high strength AlZnMg alloys and the local melting phenomena. In the Proc. of the 3th int. of Aluminium Alloys 1992, vol III, p.543 – 548.

[6] J. Sandvik, O. Jensrud, S. Gulbrandsen-Dahl, H. Hallem and J. I. Moe. Through Process Prevention of Recrystallization in Hot Formed Aluminium Structural Car Components. Mater. Sci. Forum Vols. 638-642 (2010), pp.315-320.

DOI: 10.4028/www.scientific.net/msf.638-642.315

[7] Aluminium Datasheets, Benteler Aluminium Systems Norway AS, N-2831 Raufoss.