Host Institution: University of Edinburgh
Lead Investigator: Conchur O’Bradaigh, Dimitrios Mamalis, Dipa Roy, Vasileios Koutsos
Recently, there has been a growing interest to combine composite layers and traditional metal alloys developing the hybrid materials which are also called fibre-metal laminates (FMLs). The FMLs combine the superior properties of both the constituents. They offer improved fatigue resistance and enhanced damage tolerance under impact in comparison to the individual monolithic metallic alloys or fibre reinforced polymer composites. Thus, FMLs are promising lightweight materials for future application in various industries including transport, construction, renewable energy etc. However, the ultimate performance of the FMLs is not only determined by the two constituent materials, but is also influenced to a large extent by the interface formed between them.
The interfacial bonding between the metal sheets and fiberglass plies is significantly affected by their surface roughness and surface energy characteristics. Therefore, surface treatment of the metal, prior to bonding with the composite layer, is a critical step in the bonding process which controls the mechanical performance of the FMLs.
The aim of the project is to develop a new generation of thermoplastic composite (fibre)-metal hybrid laminates using inexpensive resin infusion route. These laminates are likely to be thermoformable and recyclable/reusable.
This will allow manufacturing of hybrid laminates at a lower cost in industrial scale with enhanced properties. Once the properties are validated, these laminates have a potential to find application in transport, construction, renewable energy industries. Representatives from the relevant industries have been contacted and meetings will be held soon to get their inputs on the project findings.
This project involves three major steps:
In the first step of the project, different chemical and physical (atmospheric plasma) surface treatment methods were evaluated. Trial FMLs were manufactured with the treated metal layers. The fibre-metal bondings were qualitatively tested to downselect the optimum treatment processes for the next step of FML manufacturing.
In the second step, novel thermoplastic composite (fibre)-metal laminates (FML) were successfully manufactured with infusible thermoplastic liquid resin using Vacuum Assisted Resin Infusion technique. Few micron thickness of an organic coating was applied at the interface of the surface treated metal and the composite layer to promote bonding through in-situ polymerisation with the matrix resin.
The overall objective of the project is to develop thermoplastic composite (fibre)-metal hybrid laminates by low-cost VARTM route. The laminates will be thermoformable and recyclable with enhanced mechanical properties.