Corrosion behaviors of friction welded dissimilar aluminum alloys

• Published in: Materials characterization 2018-10, Vol.144, p.652-660
• Main Authors: Won, Sori, Seo, Bosung, Park, Jong Min, Kim, Hyo Kyu, Song, Kuk Hyun, Min, Seok-Hong, Ha, Tae Kwon, Park, Kwangsuk
• Format: Article
• Language: English
• Subjects: ALUMINIUM ALLOYS; ANODES; CATHODIC PROTECTION; Corrosion; DIFFUSION; Dissimilar aluminum alloys; ELECTROCHEMICAL CORROSION; Electrochemical impedance spectroscopy; ELECTROCHEMISTRY; Friction welding; Galvanic effect; IMPEDANCE; LAYERS; MATERIALS SCIENCE; SHRINKAGE; WELDING
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2018.08.014

Corrosion behaviors of the friction welded dissimilar aluminum alloys were investigated to understand how galvanic effect plays a role in altering corrosion properties of the dissimilar weld. From the fact that the weld had the similar OCP value to that of AA2017, it can be inferred that the corrosion characteristics of the weld is under the control of the AA2017 part in the weld and as a result, only the AA2017 part in the weld had experienced severe corrosion, leaving AA6063 under cathodic protection. Intense corrosion occurring near the interface implies that the area near the interface is placed under the effect of galvanic corrosion and there was the effective distance where the galvanic effect exerts an impact due to the increase in the resistance of the electrolyte with the distance from the interface. The disappearance of Warburg diffusion plot in Nyquist plots for the weld seemed to be the breakdown of the passivation layer related to the formation of the micro-galvanic cell, which in turn presented the shrinkage in the capacitance response, indicating that charge reactions in the form of corrosion occurred. [Display omitted] •Corrosion properties of friction welded dissimilar aluminum alloys seem to be governed by the anode part in the weld.•Intense corrosion near the interface has the limited region due to insufficient ionic transport.•Self-formation of a micro-galvanic cell is a main reason for the inferior corrosion performance.