Carbon fiber reinforced thermoplastic composites (TPCs) attracted significant attentions from the aerospace, transportation, and defense industries, due to their high specific stiffness and specific strength, outstanding thermal stability and good damage resistance, etc. As the demand of TPCs significantly increased for aerospace applications, the development of advanced joining technologies for TPC components becomes critical to ensure the structural integrity of aviation structures. This paper provides a comprehensive review of the historical development and recent advancements in welding technologies for TPCs, including ultrasonic welding, induction welding, resistance welding, and laser welding. Special emphasis is placed on ultrasonic welding due to its growing prominence in the field. The characteristics of various types of welding technologies for TPCs have been systematically discussed. Simultaneously, the strengths of the TPC joints manufactured by different welding technologies have been summarized and compared. The future development trend and research focuses for the welding technologies of TPC components are also proposed.

Interleaving thermoplastic veils has proved to enhance the interlaminar fracture toughness of carbon fibre/epoxy composites under static loading conditions. However, the fatigue delamination behaviour has yet to be investigated. Herein, meltable Polyamide-12 (PA) veils and non-meltable Polyphenylene-sulphide (PPS) veils were used for interlay toughening of unidirectional (UD) and non-crimp fabric (NCF) laminates that were manufactured using a prepreg process and resin transfer moulding process, respectively. The results of Mode-I fatigue delamination tests demonstrated a significant improvement in the fatigue life of the laminates due to interleaving. Additionally, the fatigue resistance energy has been maximumly increased by 143% and 190% for the UD and NCF laminates, respectively. The microscopy analysis revealed that the toughening mechanisms of thermoplastic veils were affected by the form of the thermoplastic veils in the laminates (melted or non-melted), the fracture mechanisms of the reference laminates and the adhesion/miscibility between the thermoplastic veils and the epoxy.