CF/PEEK interleaved laminates with PEEK film interleaving manufactured by laser-assisted forming: Microstructure and interlaminar shear strength

In this work, adding PEEK film interleaving between layers is proposed to reduce the interlaminar voids and improve the interlaminar shear strength. CF/PEEK interleaved laminates are manufactured with PEEK film interleaving and repass treatment. The porosity and microscopic features of voids are measured and characterized through the water displacement method and optical microscope. It turns out that the interleaving in interleaved laminates with repass treatment has a significant effect on reducing porosity. The crystallinity of laminates, analyzed and calculated by differential scanning calorimeter, is observed to decrease slightly with the increase of interleaving thickness. This is possibly caused by less fibers in the interleaving areas, which act as nuclei of PEEK crystallization. Interlaminar shear strength of interleaved laminates with repass treatment is higher than those without interleaving. This could be attributed to the reduction of porosity, uniform distribution of fiber/resin and the long diffusion time of chains across the interface.