Ultrastrong bonded metallization on non-weldable thermoset via additive manufacturing

Abstract The continuously increasing flight speed is the relentless pursuit of the high-speed aircrafts (HSA). However, the weak bonding between metals and thermosets in HSA antennas, susceptible to peeling and detachment, strongly limits their capacity to bear higher-speed thermal-vibrational loads. Accordingly, we pose the question that whether a multiscale interfacial interconnection strategy can provide a high-strength manufacturing solution for this hard-to-weld material combination characterized by vast physicochemical disparities. Herein, by utilizing a novel solid-state additive manufacturing (AM) strategy, called Screw Extrusion-plasticization Friction Stir Deposition (SEFSD) capable of direct metallization on thermosets, we successfully achieved a multiscale-interconnected metallized thermoset comprising macroscale interlocking, microscale anchoring and nanoscale chemical bonding at the Zn/polyimide (PI) interface. We elucidated the friction-stir-driven in-situ formation mechanisms for connections at each scale and demonstrated that the composite load-bearing effect yields a lap-shear strength of 26.73 ± 2.14 MPa, remarkably surpassing the existing methods. Furthermore, the "integrated forming and joining" nature of this solid-state AM strategy highlights its great potentials for fabricating robust, conformal hybrid components for advanced antennas and other-related applications.