Formability of two aluminium alloys

The suitability of two recently developed aluminium alloys (an Al-Mg-Mn all oy and an Al-Li-Cu alloy) for press forming applications has been examined. The characterisation involved the experimental determination of microstruc tural aspects, tensile properties, and formability parameters such as avera ge plastic strain ratio and planar anisotropy. The forming limit diagram ha s been experimentally elvaluated. A detailed analysis of the strain distrib ution profiles obtained from punch stretching experiments has been attempte d. An attempt has been mane to correlate the crystallographic texture with the formability parameters. The fracture surfaces of the punch stretched sa mples were observed using scanning electron microscopy with a view to obtai ning a correlation between fracture behaviour and formability. The alloys, in particular the Al-Mg-Mn alloy, have been found to possess good stretchab ility but both show very limited drawability. Texture analysis indicated ne gligible earing during deep drawing. These alloys are suitable for stamping applications where stretching constitutes the major proportion of the defo rmation. MST/4183.