Aluminum alloys are increasingly used in automotive structural applications thanks to their combination of low density, high strength, and good formability. Appropriate strength levels for dent resistant automotive aluminum panels may be achieved by a combination of alloy design and thermo-mechanical treatments. Unfortunately, increased strength (hardness) generally limits homogeneous plastic deformation. Thus, when shaping complex components large deformation and eventually strain localization, necking and final failure is more likely to occur. In this chapter, we endeavor to explore the best compromises between increased hardening and satisfying formability. Sheet metal shaping generates large strains and eventually strain localization. The accurate measure of metal behavior is discussed first. The following section is dedicated to the kinetics of damage development during shaping. Then metal ductility at low stress triaxiality and consequent strain localization are discussed. Finally, trimming and hemming, the most complex shaping operations to perform efficiently are analyzed providing a powerful tool for alloy design.
Part of the book: Aluminium Alloys