Development and Evaluation of Multiscale Fiber-reinforced Composite Powders for Powder-bed Fusion Process

The development of multiscale fiber-reinforced composite powders is an effective way to improve the mechanical properties and functionality of additively manufactured parts. Herein, a novel thermally induced precipitation process is proposed for preparing multiscale fiber-reinforced powders. A systematic evaluation was conducted to explore the main factors influencing powder morphology, powder flow, and microstructure. In the powder-forming mechanism, the polymer matrix is coated on the microfiber, and a film of carbon nanotubes covers the powder surface, which is promoted by heterogeneous nucleation. The composite powders comprised polyamide 12, carbon fiber (CF), and carbon nanotubes, which have been successfully applied in powder bed fusion processes including selective laser sintering (SLS). Smooth flow and powder deposition were observed, and the composite components obtained via SLS were well-fabricated using the optimized process parameters. A CF loading ratio of up to 66.7 wt% and homogeneous fiber distribution within the matrix were successfully achieved.