CASTABILITY OF Al-Li-Mg AND Al-Li-Cu-Mg ALLOYS

The objective of the present work is to study the casting characteristics of various A1-Li alloys, which include fluidity and strengths of the alloys and their interaction with cast molds. Materials investigated are Al-Li-Mg and Al-Li-Cu-Mg alloys with Li content of 2.5 wt%. The results show that sand molds with resin binders are good for A1-Li casting. Ceramic coatings can further reduce the metal-mold interactions. However, the permeability is also reduced by coating. The fluidity of Li-bearing aluminum alloys is inferior to that of A356. Compared with copper, magnesium gives a better combination of fluidity and strength to A1-Li alloys. Al-Li-Cu, together with Al-Li-Mg, are capable of providing a wide range of strength-ductility combination to casting designs. Al-Li-Mg sand cast also possesses around 80% of the strength of its wrought counterpart.