Effect of corrosion on mechanical properties for CFRP/aluminum adhesive joints under a salt spray environment

In this study, we aim to investigate the effect of galvanic corrosion on the mechanical properties of aluminum-CFRP adhesive joints. Aluminum-CFRP, aluminum-aluminum, and CFRP-CFRP adhesive joint specimens were prepared. Subsequently, the specimens were subjected to accelerated aging treatment in a salt spray environment, and the tensile shear adhesive strength, the transition of the failure surface and the deposition state and the components of corrosion products with aging time were quantitatively evaluated. As a result, in aluminum-CFRP adhesive joints under the salt spray, galvanic corrosion of the aluminum substrate occurred within 24 hours, and the adhesive-adherend interfacial strength decreased significantly compared to aluminum-aluminum and CFRP-CFRP adhesive joints. In addition, the failure mode of aluminum-CFRP adhesive joints changed from the mixed failure of interfacial failure, cohesive failure, and fiber tear failure to interfacial failure. Furthermore, it was found that the deposition amount of Al2O3 increased under the influence of the salt spray environment.