Galvanic corrosion of aluminum wrought alloys in integral hybrid components with carbon fiber reinforced plastics (CFRP) and titanium

• Published in: Materials and corrosion Vol. 69; no. 5; pp. 648 - 660
• Main Authors: Mehner, Andreas, von Hehl, Axel, Zoch, Hans‐Werner
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.05.2018
• Subjects: Aeration; Aluminum; Aluminum base alloys; Carbon fiber reinforced plastics; Carbon fiber reinforcement; carbon fibers; CFRP‐titanium‐aluminum joints; Corrosion; Corrosion resistance; Corrosion resistant alloys; Electric contacts; EN AW‐5083; EN AW‐6082; Galvanic corrosion; Impact resistance; Polymers; potentiodynamic polarization measurements; Reinforced plastics; Riveting; salt spray test; Salt spray tests; Seawater; Titanium; Weight reduction; Wrought alloys
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.201709658

Integral joints of aluminum with carbon fiber reinforced plastics (CFRPs) could help to reduce the weight of modern light weight constructions and also allow new constructions compared to the conventional riveting technology used nowadays. Aluminum–CFRP and aluminum–titanium joints frequently show galvanic corrosion if these materials are in electrical contact and if both are exposed to humidity or a watery environment. Therefore, the aim of the research in this study was the evaluation of the susceptibility to galvanic corrosion for the different aluminum wrought alloys EN AW‐5083, EN AW‐6082, and EN AW‐6056 in contact with titanium grade 2 and/or with carbon fibers. Salt spray tests of the alloys and joints of these alloys with carbon fibers and titanium confirmed the negative impact of galvanic corrosion. The alloys EN AW‐5083 and AW‐6082 with the highest corrosion resistance showed the strongest impact due to galvanic corrosion. The metallographic characterization of the corrosion attack and electrochemical measurements of the open circuit potentials and potentiodynamic polarization measurements in aerated artificial sea water revealed deeper insight into the electrochemical mechanisms for galvanic corrosion of these alloys due to contact with titanium or carbon fibers. Modern light weight constructions require joining of aluminum alloys with other light materials as titanium or carbon fiber reinforced plastics (CFRP). Electrical contact between these materials causes frequently severe galvanic corrosion at the aluminum. Therefore, the susceptibility to galvanic corrosion of different aluminum alloys was analyzed by salt spray tests and electrochemical measurements.