Enhancing the Fracture Toughness Properties by Introducing Anchored Nano-Architectures at the Metal–FRP Composite Interface

This paper presents a novel technique for improving aluminium–glass/epoxy composite interfacial bonding through the generation of metallic nano-architectures on the metal surface. Silver nanowires (AgNWs) deposited via solution casting at varying concentrations and annealed at different temperatures in an air atmosphere improved the aluminium-glass/epoxy composite fracture toughness as measured via mode I experiments. For AgNW concentrations of 1 and 3 g/m2 deposited via a single-stage process and annealed at 375 °C, the initiation fracture toughness of the aluminium-glass/epoxy composite improved by 86% and 157%, respectively, relative to the baseline composite without AgNWs. The corresponding steady-state fracture toughness of these nano-modified fibre metal laminates (FMLs) were at least seven times greater than the baseline composite. The FML variant in which AgNWs were deposited at a concentration of 3 g/m2 through a two-stage process followed by annealing at 375 °C and 300 °C, respectively after each deposition, achieved the highest steady-state fracture toughness of all nano-modified composites—a fracture toughness value that was 13 times greater than the baseline composite. Intrinsic and extrinsic toughening mechanisms dictated by the morphology of the silver nano-architectures were found to be responsible for the improved initiation and steady-state fracture toughness in nano-modified FMLs.