In order to maintain individual and public mobility compatible with the technical challenges emerging from the requirement of reducing greenhouse gas emissions, the development of energy efficient and reliable lightweight structures is a promising approach. By using hybrid structures such as fiber-metal laminates the advantages of both components, i.e., high-specific-strength and high impact resistance, can be utilized for tailored constructions and, ideally, existing manufacturing processes can be adjusted for further use.
In this study, the investigated fiber-metal laminate consists of EN AW 6082 T6, which is intrinsically bonded with unidirectional CFRP via epoxy resin, contained in prepreg system E201. The deployability of fiber-metal laminates highly depends on the materials resistance against corrosion due to the different electrochemical potential between the single components, environmental loads, such as moisture, temperature and aggressive media, as well as the resulting mechanical strength. Therefore, to optimize the bonding properties and minimize the well-known susceptibility to corrosion, the aluminum surface was laser pretreated with varying parameters and subsequently adhesively bonded and cured with E201 by a prepreg-pressing process. Using potentiodynamic polarization techniques in 0.1mol/l NaCL solution on varying surface conditions of the aluminum, differences in corrosion current and open circuit potential were detected. Microscopic images revealed distinguishable differences in corrosion products depending on the surface condition. For the hybrid laminate no significant differences in corrosion behavior were found, since the plastic component acts as an insulator between the carbon fiber and aluminum surface.
Regarding mechanical properties, a short-term fatigue testing method was employed, using load increase tests under tension-tension loading combined with thermography to determine the load and frequency dependent self-heating behavior of the fiber-metal laminate. Hereby it was possible to localize damage initiation. Investigations via in situ X-ray computed tomography showed differences in crack behavior due to the mechanical load at the CFRP-aluminum interface.