Abstract:
To address the insufficient interlayer mechanical properties of glass fiber-reinforced polyetheretherketone (GF/PEEK) composites fabricated by fused deposition modeling (FDM), resulting from the impracticality of post-process heat treatment for large-scale components and structural circuit-integrated components, an in situ thermal radiation-assisted strengthening method was proposed to enhance the interlayer mechanical properties along the build direction. The mechanical properties and interlayer strengthening mechanism of GF/PEEK composites under different thermal treatment strategies were systematically investigated by regulating the chamber temperature and in situ thermal radiation power, combined with tensile tests, interlayer tensile tests, and fracture surface morphology analysis. The results showed that increasing the chamber temperature improved the tensile properties in the horizontal direction. At a chamber temperature of 200 ℃, the tensile strength and Young’s modulus reached 62.72 MPa and 3.45 GPa, respectively. However, the interlayer tensile strength decreased from 20.61 MPa to 6.03 MPa, while the interlayer Young’s modulus increased from 1.90 GPa to 2.24 GPa. By contrast, in situ thermal radiation significantly enhanced the interlayer mechanical properties of specimens fabricated along the build direction. At a thermal radiation power of 255 W, the vertical tensile strength and fracture elongation increased to 2.34 and 7.91 times those of conventional FDM specimens, respectively, achieving mechanical properties comparable to those of post-process heat-treated specimens. Fracture surface analysis further revealed that in situ thermal radiation promoted interlayer polymer chain diffusion and molecular entanglement while reducing interfacial defects, thereby substantially improving the interlayer bonding performance. The proposed method effectively enhances the interlayer mechanical properties of FDM-fabricated GF/PEEK composites without requiring an additional post-process heat treatment, providing an effective processing strategy for the additive manufacturing of high-performance thermoplastic composite structures.