Fabrication of SiC-aluminum composites via binder jetting 3D printing and infiltration: Effects of air-assisted oxidation bonding conditions

This study systematically investigates the effects of air-assisted oxidation bonding conditions, specifically temperature (1200, 1400, 1600°C) and time (2, 4 hours) on binder jetting 3D-printed silicon carbide (SiC) samples and their subsequent infiltration with aluminum-magnesium to produce composites. SiC samples were 3D-printed, cured (green samples), air-assisted oxidation bonded under different conditions (oxidation bonded samples), and infiltrated with a mixture of molten Al and Mg powder in a 92:8 wt.% ratio (infiltrated samples). Green samples were analyzed for density and morphology, oxidation bonded samples for open porosity, and both oxidation bonded and infiltrated samples for density, morphology, and composition. Hardness measurements were carried out on infiltrated samples. Results show that higher air-assisted oxidation bonding temperature and time promote SiO 2 formation, surface smoothing, and oxidation-derived interparticle bonding, which contribute to the observed increase in density and reduction in porosity. The formation of SiO 2 during air-assisted oxidation bonding also inhibits Al 4 C 3 formation, improves wettability and, consequently, facilitates infiltration. Since no inert-atmosphere control experiment was conducted, the observed densification and porosity reduction are interpreted as a result of oxidation-assisted bonding and SiO 2 formation, rather than isolated SiC particle necking. Prolonged air-assisted oxidation bonding leads to a reduction in the hardness of infiltrated samples, attributed to increased contribution of the infiltrated Al phase. Air-assisted oxidation bonding at 1600°C significantly reduces pore volume, limiting infiltration efficiency. XRD and SEM/EDS phase analysis of infiltrated samples confirm the presence of SiC, Al, Si, SiO 2 , MgAl 2 O 4 , and Mg 2 Si, indicating interfacial reactions. Because phase composition of samples evolves during air-assisted oxidation bonding and infiltration, density trends are discussed alongside changes in composition and porosity. These findings demonstrate that oxidation plays a dominant role in bonding and densification behavior under air atmosphere and offers new insights into additive manufacturing of high-performance composite parts for various applications including the aerospace, automotive, and railway industries.