Dependence of Mechanical Behavior of Adhesive-Bonded Hybrid Multi-materials on the Properties of Base Materials

Currently, automotive and wind-energy-generation industries worldwide are facing issues in achieving lightweight efficiency and meeting enhanced safety standards. Multi-materials are increasingly being adopted to resolve these issues simultaneously. Therefore, technologies for bonding multi-materials have been gaining importance. Adhesive-bonding methods using structural adhesives have been developed for their weight-reduction capabilities and superior stress distribution, compared to traditional mechanical-bonding methods. However, sufficient research on the mechanical properties of adhesive-bonded multi-materials and their dependence on the characteristics of the base materials and bonding strength is lacking. In this study, two multi-materials, DP590–A356 and SS330–A5052, are bonded using a structural adhesive at adhesion strengths of 10, 22, and 30 MPa, and their mechanical behaviors are studied through tensile tests. The results show that the fracture elongation of aluminum increases as the adhesion strength increases, for both multi-materials. However, in DP590–A356, the decrease in the fracture elongation of A356 is more than that in A356 alone, while in SS330–A5052, the increase in the fracture elongation of A5052 is more than that in A5052 alone. The results of tensile tests on a third multi-material, DP590–A5052, and SS330–A5052 show that while the fracture elongation of A5052 increases for both multi-materials, the fracture elongation of steel decreases. Moreover, the decrease in the fracture elongation of SS330 is more than that of DP590. The tensile tests results are analyzed through digital image correlation and the deformation distributions according to the mechanical properties of steel and aluminum are verified.