Adhesives bonding of a titanium alloy to a glass fibre reinforced composite material

Experimental results for 90° peel tests are presented for alternative titanium surface treatments. Based upon these results, sodium hydroxide anodisation (SHA) and surface cleaning by Excimer laser were selected for further study. The durability of a titanium/glass fibre composite lap joint in a hot/wet environment was investigated by single lap shear testing. Both thermosetting and thermoplastic composites were evaluated using two aerospace industry standard film adhesives. Surface treatment by Excimer laser resulted in a five-fold increase in peel strength (dry), but the environmental durability was shown to be poor. In comparison, SHA of the titanium resulted in relatively high peel strengths and provided a durable composite/metal bond.