Exploring AlSi12 powder size for laser powder bed fusion of multi-materials under oxygenated atmosphere

• Chemically untreated AlSi12 powder is used to manufacture multi-material metal-ceramic parts. • New manufacturing parameters enable the in-situ oxidation of untreated AlSi12 powders. • The implemented process allows for the simple fabrication of multi-material ceramic-metal parts using conventional machines. • A coarse-grained powder improves cohesion at the metal-ceramic interface and surface roughness (Rz) compared to a fine-grained powder. Although Powder Bed Fusion with Laser Beam (PBF-LB) is increasingly being used to produce functional components, the fabrication of integrated metal–ceramic multi-materials parts remains challenging. This study presents a single-powder PBF-LB strategy enabling the production of AlSi12/alumina multi-materials parts. The ceramic phase is generated in situ through localized oxidation, which is induced by a high surface energy density under oxygen partial pressure. This study aims to evaluate the influence of particle size on the manufacturing of multi-material parts. Two powders with identical composition but with different particle sizes (coarse and fine) were characterized in terms of their physicochemical properties and performance under processing conditions. The coarse powder exhibits the best fluidity and absorbency, indicating superior powder spreading and laser beam absorption. Conversely, the friction forces between particles related to the fine powder lower fluidity, result in increased resistance to ejection during high-energy-density conditions, which are necessary for forming ceramic zones. The results show that both powders can be processed without any chemical pretreatment and that new PBF-LB parameter windows enabling stable in situ oxidation, have been identified. The use of coarse powder improves surface roughness as well as a metal-ceramic interface with fewer porosity and defects. This highlights the advantages of coarse powder for manufacturing multi-material components. These findings demonstrate the feasibility of producing metal–ceramic architectures using a single aluminum alloy, without prior chemical treatment. The presence of both conductive metal regions and dielectric ceramic zones creates opportunities for the integration of multifunctional components into various advanced applications.