Novel AA7075/AA2124-SiC-17p laminated structures for aerospace applications: A Comparative study into the mechanical performance of PA6 and PA66 composite interlayers

Abstract

Multimaterial designs consisting of metallic and polymeric material are aimed to reach high lightweight potential. This study presents novel hybrid structures with different interlayer of thermoplastic composites not previously reported in the literature for multi-laminated composites. The metal-polymer-metal hybrids comprise of polyamide 6 (PA6) or polyamide 6,6 (PA66) composite reinforced with 15% of short glass fiber as a sandwich layer. AA7075/AA2124-SiC-17p composite laminates are bonded through hot pressing connection. Mechanical properties of the structures are experimentally investigated from the point of maximum shear strength between dissimilar laminates, resistance to fracture and energy absorbing capacity. Scanning electron microscope (SEM) analysis of fracture surfaces is carried out after mechanical characterization. Short beam three-point-bending tests show that the laminate on which the load is applied is of great importance for the asymmetric hybrid structures. Shear dominant failure is only visible when the bending load is performed from the AA7075 surface. Single-edge notched bending (SENB) test results indicate that there is no significant difference between two configurations in terms of the Mode-I fracture toughness. V-notch Charpy impact tests reveal that the interlayer of PA6 composite contributes to a 13.15% more absorbed energy than that of the PA66 interlayer.