Enhancing interlaminar fracture toughness and shear strength of carbon fiber composite laminates via orientation of nickel-plated short carbon fibers in a magnetic field

This study aimed to enhance the interlaminar mechanical properties of carbon fiber composites by incorporating nickel-plated short carbon fibers (Ni@SCFs) between adjacent layers in a magnetic field. Herein, non-flocked composites, flocked composites with unoriented Ni@SCFs, and flocked composites with oriented Ni@SCFs using a magnetic field were fabricated to investigate the impact of fiber orientation on the mode I interlaminar fracture toughness (GIC) and interlaminar shear strength (ILSS) of the composite laminates. It was observed that Ni@SCFs were distributed at varying vertical angles between adjacent layers under the influence of the magnetic field. The areal density of oriented Ni@SCFs was systematically increased, resulting in notable enhancements in both initiation and propagation of GIC for flocked composites. At a flocking density of 6 g/m2, maximum values reached 533 J/m2 and 769 J/m2 respectively, representing a substantial increase of 52 % and 63 % compared to non-flocked composites. Additionally, the ILSS of flocked composites with oriented Ni@SCFs significantly improved to 55.83 MPa at a flocking density of 2 g/m2, indicating an increase of 27 % over non-flocked composites. The oriented Ni@SCFs played a crucial role in inhibiting crack propagation through the fiber bridging effect.