Considerations for the industrial application of structural adhesive joints in the aluminium–composite material bonding

The composite materials of the polymeric matrix reinforced with carbon fibre have an extensive industrial application as they provide light and resistant structures. However, in many products (automobiles, aircraft, etc.) the structural adhesive parts must be joined to other components manufactured with aluminium alloys. The use of structural adhesive to carry out these bonds may be a good alternative if a specific design of the adhesive joint is carried out maximising its performance and reducing its limitations. In this respect, one of the most relevant aspects of the design of the joint consists of the selection of the structural adhesive and the most appropriate surface treatment for the substratum. The present paper describes a procedure to optimise this decision by means of the combination of experimental techniques with multi-criteria decision tools. This methodology allows selecting, amongst the various alternatives, the adhesive and surface treatment better combining mechanical performance and adaptation to the manufacturing process. Thus, it has been concluded that polyurethane adhesive with a peel ply surface treatment for carbon fibre, and sandpapered for aluminium, are the best alternatives.