Laser Powder Bed Fusion of High-Strength Aluminum Matrix Composites

E. Parsons
MIT Lincoln Laboratory,
United States

Keywords: composites, powder fabrication, aerospace

Summary:

The mechanical and thermal properties of particle-reinforced metal matrix composites (MMCs) are attractive for high-performance defense and space applications, but fabrication of MMC components with conventional methods is difficult, costly, and typically limited to components with simple geometry. Additively manufacturing particulate MMCs with laser powder bed fusion (LPBF) would be an ideal method, but the laser consolidation of these materials has been largely unsuccessful in matching the properties of conventionally produced MMCs. The challenges include hot cracking of the matrix, spreading the heterogeneous powder, distributing small ceramic particles, and forming a strong bond between the metal and the ceramic. Here, by mechanically alloying high-strength aluminum alloys and ceramic particles, we manufacture aluminum composite powders with morphology tuned for AM process conditions. The ceramic content, chemistry, and particle size are varied. Using LPBF, we achieve dense consolidation of these powders and demonstrate the potential for highly-reinforced, high-strength aluminum alloys to be used in defense and space applications requiring complex geometries, short lead times, or low part numbers.