Characterization of flow behavior of graded regolith-metal powder mixtures

Abstract

The Moon, rich in resources, is vital for space exploration. Space manufacturing requires in situ resource utilization due to high shipping expenses. Among these resources, lunar regolith is abundant but poorly suited for additive manufacturing due to its low flowability. This study investigates the effect of incorporating spherical stainless steel (SS316L) particles into the angular regolith simulant LHS-1 (lunar highland simulant) to improve granular flow behavior. By systematically varying the SS316L volume fraction and particle size distribution, we show that adding 50 vol% SS316L significantly enhances flowability, with larger particle size distributions providing the greatest improvement. While the packing densities of the mixtures increase with SS316L addition and remain comparable across particle size distributions, the dynamic angle of repose decreases substantially, demonstrating a decoupling between packing and dynamic flow behavior. This improvement is attributed to particle shape heterogeneity, where spherical metal particles likely reduce frictional interlocking and facilitate rearrangement within the angular regolith matrix under shear. These findings demonstrate the potential of engineered regolith–metal powder blends to achieve both improved packing quality and enhanced flow performance, enabling their use in powder-bed additive manufacturing processes for future lunar applications. Graphical abstract