Anisotropic tribological behavior and fiber orientation mechanisms of CF/PEEK composites fabricated via PBF additive manufacturing

Powder bed fusion (PBF) has emerged as a highly promising additive manufacturing technology for fabricating high-performance carbon fiber reinforced polyetheretherketone (CF/PEEK) composites. However, the underlying correlation between the inherent manufacturing process, microstructural evolution, and resultant macroscopic properties remains elusive. This study systematically elucidates the anisotropic tribological behavior of PBF-printed CF/PEEK composites driven by process-induced fiber orientation. Microstructural analysis reveals that the shear flow during the powder-spreading phase induces a preferential alignment of carbon fibers. Consequently, the X-Z plane exhibits a higher fiber cross-sectional area fraction (7.88%), where the vertically oriented fibers act as robust "load-bearing micro-pillars". This unique micro-architecture significantly resists plastic deformation and plowing, reducing the specific wear rate to 2.0 × 10⁻⁶ mm³/Nm—an order of magnitude lower than pure PEEK, and 28% lower than the perpendicular X-Y plane. To validate the structural superiority of this composite under extreme engineering conditions, gear meshing tests were conducted, demonstrating a 3.8-fold enhancement in wear resistance based on the mass loss proportion. These findings provide profound insights into tailoring the anisotropic architecture of polymer composites via PBF processing, offering a theoretical paradigm for designing advanced multifunctional components.