New Alloy Development for AM: High Strength Aluminums HS1 & HS2

With the rapid industrialization of Laser Powder Bed Fusion (LPBF), it became evident that suitable high strength aluminum alloys were not available. High strength alloys like 2000, 6000, and 7000 series couldn't be printed without defects. After evaluating several potential systems, the Al-Mn-Cr system was selected for its precipitation hardening capabilities and lack of deep eutectic, potentially avoiding hot cracking. Zr was added for grain refinement and Mg for solution hardening.

The presentation will also cover powder properties, the printing process, heat treatment, and printed parts' properties, including real examples. The gas atomized powder results in spherical particles with minimal satellites and non-spherical particles, ensuring good flow and defect-free parts within a wide processing window. Post-printing, parts are direct aged for times ranging from 2 to 14 hours at 350-400°C (660-750°F), higher than standard aluminum alloys, making the material stable at operating temperatures at 250°C (480°F) and potentially higher. HS1 has shown high strength at higher operating temperatures, while HS2 exhibits even higher strength at lower temperatures, both tested using the LPBF/SLM printing process.