Combined high-throughput computational and experimental screening of aluminum alloys suitable for additive manufacturing from scraps

Abstract

To meet societal goals like climate neutrality by 2050 and a circular economy, material discovery must be faster and more flexible, especially as raw material costs and supply chain issues increase. Advanced technologies like computational screening, 3D/4D characterization, and machine learning enable rapid responses to these challenges. A new Al-based alloy suitable for additive manufacturing (AM) derived from scrap metal mixtures was developed using high-throughput alloy screening paired with synchrotron radiation based experimental validation. The new alloy is intended for aerospace applications and has to meet requirements such as low sensitivity to hot-cracking, minimal solidifaction interval, appropriate strength and elongation, etc. In high-throughput computational screening, up to 10k alloy compositions were generated by mixing the scrap alloys at different ratios. The CALPHAD method was used for equilibrium and non-equilibrium simulations to assess key parameters, including phases, solidification intervals, and mechanical properties like yield strength and hot-cracking sensitivity. A random forest model predicted properties from simulations and literature, while a multi-objective evolutionary algorithm filtered alloys with target characteristics. Uncertainty calculations addressed compositional variations in scrap, ensuring robust designs. For experimental validation, selected alloy compositions were synthesized by conventional casting, remelted and subjected to laser line scan testing to investigate the effect of different solidification rates on the material. Satic synchrotron tomography scans were taken to analyse the microstructure in 3D. Finally, a potential composition suitable for additive manufacturing was selected for powder production and in-situ laser powder bed fusion experiments were performed during microtomography to confirm the processability of the alloy.