Mechanism of Enhanced Flowability/Spreadability in 3D Printed Ni Alloy Powder

Improving powder flowability is essential for better three-dimensional (3D) printing. The powder can achieve enhanced flowability by optimizing the surface morphology or composition of powder used in 3D printing. Herein, flow behavior of the powder was improved by surface modification of IN718 microspheres with the acid treatment. The acid treatment increases surface roughness and wettability while decreasing surface energy, the dominant factors in the improved flowability of acid-treated IN718. Notably, the acid-treated IN718 surfaces revealed an apparent contact angle of 129 degrees due to the change in surface energy. Therefore, the impact of surface roughness and surface chemical composition was linked to the surface energy of acid treated IN718. Furthermore, the flowability of acid-treated IN718 powder was about 17.31 s to flow the 50 g of powder, whereas there