Experimental investigation of parameters which affect to bonding performance of metal and composite parts

Along with the development of the aviation industry low density has become increasingly important in this area. For this reason, the use of composite structures has been increased in the course of time. Instead of combining the usage of mechanical fasteners, the use of the bonded structure becomes one of the most efficient parameter for the lightweight structures. Therefore, the use of bonding applications becomes increasingly common to combine the parts. There are many parameters that affect the bond performance. One of the most important parameter is the process of preparing the surface of adhesion. Adhesion strength can be increased with some of the surface preparation techniques. Another important parameter that affects to the bond performance is the adhesive bond thickness. Thickness changes in adhesion can create stress concentrations which reduce the bonding strength in adhesive. Adhesion performance can be increased with the thickness control methods. Besides, other factors like humidity, temperature, pressure and adhesive curing methods, can affect bonding performance as well.In this study, methods of surface preparation for bonding composite or metal parts are theoretically analyzed, for metal samples, phosphoric acid coating, #80 and #180 the number of aluminum powder spraying methods, for composite samples, Scotchbrite, peel ply, grit blast, #80 and #400 sanding methods were applied. These samples are tested with the tensile strength and resistance to environmental conditions and the results have been obtained. The affects of surface preparation to bonding performance could be observed. Similarly, the therotical informations were given about bond line thickness control and samples were prepared using ScrimCloth and Micro Beads methods. The tensile tests were made on the samples and the results have been obtained. The affects of thickness control to bonding performance could be observed.Key Words : Composite, Surface Preparation, Adhesive Bonding