Inspiration of repass in‐situ tempering engineering strategy for shape‐performance integrated manufacturing of carbon fiber reinforced polyetheretherketone (CF/PEEK) thermoplastic composites

Abstract Advancing in‐situ forming manufacturing techniques for green recyclable thermoplastic composite (TPC) remains a challenge. Herein, the effects of a laser‐assisted repass annealing treatment on the surface roughness, porosity, crystallinity, mechanical properties, and warpage deformation of carbon fiber‐reinforced polyetheretherketone (CF/PEEK) composites were investigated in this work. Specifically, four methods of laminate manufacturing were implemented: no repass, single repass, double repass, and opposite single repass. It is found that the repass treatment enhances surface smoothness of the laminate, promoting resin fusion and reducing the occurrence of pores. Simultaneously, the close‐packed CFs arrangement within the laminate hinders crystal growth, and the crystalline region undergoes rapid melt and crystallization during the repass procedure. Additionally, reducing the porosity and implementing a repass treatment led to a 405.41% increase in PEEK molecular chain diffusion time, thereby enhancing the mechanical properties of the laminate. Meanwhile, the double repass treatment reduced warpage deformation by 20.83%. This can be explained as the repass treatment supports the de‐orientation behavior of PEEK molecular chains, which leads to a reduction in residual stresses and the suppression of warpage deformation defects. In summary, this work validates the feasibility of repass annealing treatment and inspires the birth and development of a potential optimization process for TPC in‐situ forming. Highlights The mechanism of the effect of the repass consolidation process on the warpage‐deformation, porosity, crystallinity, and mechanical properties was revealed. Optimized method for calculating warpage‐deformation using CMM technology. The repass treatment reduced residual stresses and suppressed warpage by promoting molecular chain de‐orientation. This work validates the feasibility of ICAT repass treatment and inspires the inception and development of a potential optimization process for ICAT.