Numerical Investigation of the Galvanic Corrosion Behavior of a Joint between Steel and Aluminum Alloys Produced by Friction Stir Joining

Abstract

This study establishes a numerical model to study the galvanic corrosion behaviors of four galvanic couples located along the front and the back surfaces of a friction stir welded joint of dual-phase steel and aluminum alloys joined at an offset of 0.5 mm and exposed to a neutral environment. The results are initially validated with the experimental methods and are found to be in good agreement. The galvanic corrosion behaviors of the couples are further explored by subjecting the model to some electrochemical scenarios, such as the effects of electrolyte depth and cathode-to-anode surface area ratios. Furthermore, the model is capable of tracking the moving boundaries of the corroding surfaces of the galvanic couples. This overall approach presented herein provides a suitable framework for understanding the galvanic corrosion behavior that exists along a heterogeneous joint involving multiple galvanic couples.