Abstract: The Titanium/Graphite Hybrid Laminates (TiGr) have been widely used in aeronautical structures for their excellent performance. The adhesive properties of the titanium plate and the composite in the TiGr laminates will affect the stiffness and failure modes of the TiGr laminates. However, the adhesive property of the titanium plate and the composite are greatly influenced by the processing technology. In this paper, adhesive property of titanium-composite joints with different surface treatments on titanium surface was investigated based on floating roll peeling methods and range analysis. The peeling results show that the titanium-composite joints with twice plasma treatment have the highest peeling resistance of 6.914 kN/m, but the titanium-composite joints with twice plasma treatment and resin protection have the the lowest peeling resistance, which is 2.139 kN/m. Three failure patterns of the adhesive interface between titanium and composite happen during the peeling process. That is the adhesion failure between the titanium plate and the adhesive film, the cohesion failure of the adhesive film, and the adhesion failure between the adhesive film and the composite. The peel resistance reaches the highest when the cohesion failure of the adhesive film occurs. According to the experimental results, the adhesive property is weakened with the resin protection applied on the titanium surface. In addition, the grit blasting prior to the plasma treatment weakens the adhesive property, as compared to the property with no grit blasting prior to plasma treatment.

Key words: surface treatment, titanium and alloys, composite, peel, adhesive property