Effect of Scandium on Wire Arc Additive Manufacturing of 5 Series Aluminium Alloys

Scandium has a known beneficial effect on the strength of aluminium alloys. In particular, the strength of weld metal in a 5 series alloy can be significantly increased by scandium additions to either the weld filler rod or the base metal plate. The emerging technology of wire arc additive manufacturing (WAAM) provides for fast welding deposition rates of 3D structures. Because the whole piece is weld metal, scandium additions to the weld wire would appear to offer an opportunity for increased strength of articles produced by WAAM processes. This paper examines various addition levels of scandium to AA5183 aluminium alloy. AA5183 welding wire is commonly used for welding of AA5083 plate, commonly used in marine and automotive applications. It was shown that significant levels of strength improvement were possible with scandium additions of 0.2–0.5%. Further additional strength improvement was made possible by a post-weld heat treatment.