Characterization of Flow Behavior of Graded Regolith-Metal Powder Mixtures using a Rotating Drum*

The Moon, abundant in resources, is vital for space exploration. Due to high transportation costs, in situ resource utilization is crucial for manufacturing in space but pure lunar regolith is cohesive and flows poorly. This study investigates the flow characteristics of graded lunar simulant and the enhancement of these properties by adding smaller stainless steel (SS) particles. The goal is to improve regolith flowability with the inclusion of SS powder and evaluate the effect of particle size distribution (PSD) of the SS particles on the flowability of the regolith simulant particles. Flow behavior measurements such as packing density, static and dynamic angle of repose are related to the particle sizes. Such powder properties are essential for numerous applications, including additive manufacturing (AM), a process of constructing objects layer by layer using materials such as wire or powder fused by heat sources like laser or electron beam. Key metal AM processes, such as laser powder bed fusion (LPBF) rely on powder, and poor powder flow can lead to defects in the final parts. To evaluate powder flow properties analogously to LPBF, it’s essential to use techniques that replicate the final process conditions, especially the stress state during AM. The rotating drum method, which makes the powder flow and tumble, simulates the dynamics of powder in various processes like LPBF in support of Lunar manufacturing.