Effect of a Surface Treatment of Aluminum Alloy on Fatigue Properties of Friction Stir Spot Welded Joint between Aluminum Alloy and CFRP

摘要

In order to investigate the effect of a surface treatment by anodic oxidation treatment generating an anodic porous alumina layer on the surface of the aluminum alloy on the joint of the aluminum alloy and the CFRP welded by the Friction Stir Spot Welding, the microscopic observation of the welding area, the fatigue tests were carried out, and the mechanism of the fracture has been investigated. The result of the microscopic observation of the welding area shows that a number of pores generated in the CFRP, and according to the result of the fatigue test, the fatigue strength was improved by the application of this treatment. Also, the welding area and the stability of these area were increased by the application of this treatment. In addition, the proportion of the adhesion area in the welding area of the specimen with treatment was higher than the proportion of the specimen without treatment. Moreover, for the fracture mechanism, for specimen without the treatment, the interfacial failure is regarded as the main reason of the fracture while the cohesive failure is regarded as the main reason of the fracture of the specimen with the treatment.