Characterization of interlaminar properties across processing parameters of consolidation of <scp>CF</scp>/<scp>PEKK</scp> composites for benchmarking performance

Abstract

Abstract Carbon fiber reinforced thermoplastics (CFRTP) are gaining momentum, largely due to the benefits of in situ curing, which eliminates long cure times. This makes them an ideal choice for rapid manufacturing using automated tape‐layup machines. Given the sensitivity of thermoplastic properties to processing parameters, a detailed experimental characterization of interlaminar consolidation capacity is crucial before adoption. In this study, we placed poly‐ether‐ketone‐ketone (PEKK) thermoplastic tapes using a robotic tape‐layup machine and consolidated them via compression molding. The resulting samples were experimentally characterized to obtain the thermo‐mechanical performance as a function of consolidation pressure, duration, and ply‐stack orientation for a total of 15 testing cases. Our findings show that the modulus and strength of the laminates with similar ply‐stack orientation can change significantly by up to 200%, based on different processing parameters. The time for interlaminar chain diffusion emerged as the most influential processing parameter. This work provides a benchmark for properties to be targeted with automated fiber placement techniques and underscores the importance of detailed experimental characterization in adopting such techniques. Highlights Processing parameters can affect the tensile strength of CF/PEKK by up to 200%. Consolidation time is the most influential processing parameter for CF/PEKK. Crystallinity only affects ultimate tensile properties and not stiffness. In‐plane shear is primarily controlled by interlaminar chain diffusion. Outgassing in the interfibrous region can cause significant voids.