Controlling factors determining flowability of powders for additive manufacturing: A combined experimental and simulation study

Powder flowability affects dynamic powder behavior during additive manufacturing and varies depending on particle size distribution, particle morphology, and surface features. In this study, Inconel 718 alloy powders were prepared by gas atomization (GA), plasma atomization (PA), and plasma rotating electrode process (PREP). The flowability was experimentally evaluated by the avalanche angle. With the help of numerical simulations, the individual effects of particle size distribution, particle morphology, and particle surface features on flowability were analyzed. The results showed that the PREP powder possessed the best flowability among the three powders. The PSDs were slightly different, but these differences had almost no effect on their flowability. Nevertheless, the excellent flowability of the PREP powder was due to the high particle sphericity and the thin surface oxide film. If the environmental factors are well controlled during the handling, PREP has a natural advantage over GA and PA in terms of flowability. • Flowability of powders for AM was evaluated by experiment and simulation. • Effects of PSD, particle morphology and surface feature on flowability were evaluated. • Surface roughness that correlated to the oxidation altered powder flowability. • High sphericity and thin oxide film contributed to the superb flowability of PREP powder.