Additive manufacturing of aluminum metal matrix composites: Mechanical alloying of composite powders and single track consolidation with laser powder bed fusion

The thermomechanical properties of particle-reinforced metal matrix composites (MMCs) are attractive for many structural applications, but fabrication of MMC parts with conventional methods is difficult, costly, and typically limited to simple geometries. 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 spreading the heterogeneous powder, distributing small ceramic particles, and forming a strong bond between the metal and the ceramic. Here, by mechanically alloying AlSi10Mg and TiB2, we manufacture highly-reinforced aluminum composite powders with morphology and composition tailored for LPBF process conditions. We show that this powder flows and packs similarly to gas atomized aluminum powder and can be consolidated into smooth, continuous tracks. Moreover, the method of feedstock powder production is scalable and commercially viable. Our results demonstrate conditions under which MMCs with high ceramic loading can be produced by additive manufacturing, potentially opening up many new applications for these high-performance materials.