Extrusion-based additive manufacturing of SS316L/CNT nanocomposites: evaluation of feedstock properties and 3D-printing feasibility

This study investigates the extrusion-based additive manufacturing (AM) of SS316L and SS316L/multi-wall carbon nanotubes (MWCNTs) nanocomposite, focusing on the impact of 1 wt.% MWCNT addition on feedstock's rheological properties and printability. The presence of 1 wt.% MWCNT in the feedstock improved the nanocomposite's printability, as evidenced by a 14% increase in shear sensitivity, and a decrease in the density difference between the feedstock and the printed part from 0.10 g/cm3 to 0.09 g/cm3. Densitometry showed the nanocomposite's printed density was 4.59 +/- 0.03 g/cm3, compared to 4.75 +/- 0.05 g/cm3 for SS316L. Additionally, rheological analysis showed increased viscosity at low shear rates, enhancing flow control during printing. The composite feedstock exhibited superior surface appearance and improved homogeneity, demonstrating the potential of MWCNTs to enhance the quality of metal parts in extrusion-based AM.