Additive manufacturing (AM) processes could lead to considerable change in our manufacturing routes, as well as enabling significant material, lead time and cost reductions. New manufacturing paths involve new manufacturing steps, fundamentally different from the conventional thermo-mechanical processes used in subtractive methods. Therefore the materials used in wrought products are not always suitable for AM processes. Yet often conventional wrought alloys are used in AM, and the properties of the AM materials are simply compared to their wrought equivalents, missing out on the great potential of AM regarding material design freedom.
Thanks to the nature of AM processes new alloys can be developed for AM applications in a very time and cost-effective way. Wire plus Arc Additive Manufacture (WAAM) is an AM process using a wire as feedstock and an electric arc as a heat source. WAAM can be used to build large-scale components in various materials such as titanium, Inconel, steel and aluminium. Numerous aluminium alloys have been shown to be suitable for WAAM, but the number of available high strength alloy wires on the market is very limited. To test a new alloy a new wire can be manufactured but this is a very expensive route, both in terms of cost and time. , This is especially so if several iterations are required to optimise the chemical composition of the material. A much more cost effective and rapid solution is to use different wires and mix them in situ to produce new alloys.
Through the NEWAM and IAWAS projects the development of new aluminium alloys using WAAM has been investigated. Up to three wires have been used to deposit customised chemical compositions in a wide range of aluminium copper magnesium alloys. Other processes such as Wire Laser Hybrid Additive Manufacture have been used to include alloying elements such as zinc and lithium these are challenging due to their low vaporisation point and reactivity at high temperatures. Through these methods, aluminium zinc, aluminium scandium, and aluminium lithium alloys have been deposited and wide range of chemical compositions investigated and optimised. The results of some of these studies will be reported.