Participants: NLR, INTA, Airbus and ONERA
Several novel high strength aluminium alloys are currently being investigated for application in Additive Manufacturing (AM). Great advancements have been achieved on processing aluminium alloys with Laser Powder Bed Fusion (L-PBF) and Directed Energy Deposition (DED). However, high-strength aluminium alloys tend to crack during molten material processing, and in addition, aluminium’s high affinity with oxygen, high reflectivity, and high conductivity decrease AM processability. To address this, several studies have focused on adapting the material composition to the AM process. It was found that the addition of chromium can increase the process stability and absorption properties when using L-PBF. Despite the advancements on alloy development for AM, there is still a big gap with respect to material qualification of these novel alloys.
In this GARTEUR Action Group 36, L-PBF and DED processing of a 400-500 MPa novel high-strength aluminium alloy concept, Scancromal® (Sc-modified aluminium alloy with chromium addition), was evaluated. The study involved the powder characterisation to evaluate the flowability and powder quality. Then, a process parameter optimisation was carried out for both processing routes. An extensive mechanical test campaign was carried out with material that was processed by the more mature LPBF process. The cryogenic-, room- and high-temperature behaviour was evaluated in static and fatigue. Regarding the DED process, the microstructure evolution based on different nozzle heads was evaluated. After the parameter optimisation, the microstructure of the as-built parts was analysed using optical microscopy and scanning electron microscopy. In addition, the phase formation and grain structure were studied in both processes for different heat treatment conditions. Currently, all the testing and characterisation tests have been concluded, and the reporting is being carried out by the AG partners.
