Influence of feedstock characteristics and printing parameters on material extrusion additive manufacturing of aluminum-based powder-binder mixtures

Aluminum and its alloys are widely used in industrial fields such as aerospace and automotive due to their excellent rigidity-to-weight ratio. However, the oxide layer that forms on the surface of aluminum poses challenges for powder metallurgy processes, particularly during sintering. Material extrusion additive manufacturing, a powder-binder-based process, offers advantages of rapid prototyping and low cost but remains largely unexplored for aluminum systems. This study investigates each step of the material extrusion process for AlSi10Mg powders. Feedstocks formulated with 65 vol.% of powder, 25–27 vol.% of paraffin wax, 2 vol.% of stearic acid, and 6–8 vol.% of ethylene–vinyl acetate were printed to produce simple and complex geometries. It was established that the particle size distribution is a critical parameter driving the feedstock behavior and stabilizing its printability. Printed parts underwent thermal wick-debinding at 250 °C for 2 h under argon followed by liquid-phase sintering varying from 565 to 575 °C for 2 h in a nitrogen atmosphere, using sacrificial magnesium granules as an oxygen getter. The sintered parts reached a relative density up to 98% and exhibited an adequate microstructure. However, further optimization is required to mitigate warping during sintering and improve dimensional stability.