Enhanced Mechanical and Wear Performance of Carbon Fiber‐Reinforced PA6 Composites Fabricated by Screw Extrusion Additive Manufacturing

ABSTRACT Fused deposition modeling 3D‐printed parts remain challenging for engineering applications due to anisotropic mechanical behavior arising from weak interlayer bonding. In this work, an engineering‐applicable carbon fiber‐reinforced polyamide 6 (PA6/CF) composite was successfully fabricated via screw‐based 3D printing. The 3D‐printed composite exhibited a favorable combination of tensile strength (76.8 MPa), flexural strength (121.0 MPa), impact strength (25.9 kJ/m 2 ), and interlayer bonding strength (45.6 MPa). Compared with Neat PA6, these properties were enhanced by 42.5%, 32.2%, 379.6%, and 87.7%, respectively. This favorable comprehensive mechanical performance was attributed to the synergistic effect of CF and a compatibilizer, maleic anhydride‐grafted styrene–ethylene–butylene–styrene copolymer (SEBS‐g‐MAH). SEBS‐g‐MAH played a dual role: it reacted with PA6 to form “molecular bridges” at the CF–matrix interface, enhancing chain entanglement, interfacial adhesion, and stress transfer, and it promoted interlayer chain diffusion during 3D printing by reducing the crystallization rate of PA6, thereby improving interlayer bonding. In addition to enhanced mechanical performance, the PA6/CF composite demonstrated superior tribological properties compared with Neat PA6, with a 65.3% lower friction coefficient (0.26), a 90.1% lower specific wear rate (2.83 × 10 −5 mm 3 /Nm), and improved frictional stability. This study provides insights into designing engineering‐applicable polymer composites for additive manufacturing.