Investigation of joint strength in PP-GF / aluminum hybrid components using a novel bulk forming process

Abstract Hybrid components can effectively combine the advantageous properties of different materials, such as the excellent mechanical performance of metals and the light-weight characteristics of polymers. This study therefore investigates the manufacturing and mechanical performance of hybrid components comprising a metallic tube with a polymer core. The hybrid parts were produced by pressing a polymer into the metallic tube using a compression process at temperatures ranging from 100 °C to 150 °C, which is below the polymer’s melting temperature. This novel process differs significantly from conventional methods, such as injection molding with overmolding, as it enables simultaneous deformation of the metallic tube and forming of the plastic in solid state. To analyze the bond strength and assess the mechanical interlocking and adhesion at the interface, push-out tests and torsional loading experiments were conducted. The bond strength reached values of up to 8.4 MPa. Further, a finite element model was developed to simulate the forming process, enabling analysis of interfacial contact pressure, geometry variation, and local stress and strain states to provide deeper insights into material flow and deformation mechanisms.