Additive Manufacturing and Joining of Metal-Polymer/Composite Hybrid Structures in Aviation

In light of stringent environmental regulations, engineers and designers are under increasing pressure to reduce the structural weight of conventional aircraft to mitigate greenhouse gas emissions. The advent of electric-powered and hydrogen-powered aircraft concepts demands the incorporation of heavy battery blocks, large fuel tanks, or cells, which, in turn, makes high-performance lightweight structures indispensable for enhancing the operational range of future aerial and terrestrial vehicles. Metal-fiber-reinforced polymer hybrid structures (MP-HS) stand as potential solutions to meet these demands. These hybrid structures exhibit distinct solid interfaces characterized by sharp gradients in material properties. The inherent disparities between metals and polymer/composites pose substantial engineering challenges, demanding innovative and materials-friendly manufacturing approaches. Presently, the state-of-the-art production of MP-HS, such as the hybridization of metals with composites through semi-automated lamination techniques, is time-consuming and often unable to accommodate complex geometries, particularly those featuring internal 3D features. The integration of metal and fiber-reinforced polymer additive manufacturing (AM) with energy-efficient friction-based joining technologies holds the promise of overcoming these limitations. This chapter explores recent developments in the AM and joining of metal-fiber-reinforced thermoplastic hybrid structures with an emphasis on aircraft materials.