Corrosion issues in joining lightweight materials: A review of the latest achievements

Multimaterials assemblies and, in particular, assemblies made of lightweight components are of utmost relevance in many technical applications. These assemblies include multimetal, metal-polymer, metal-adhesive, and metal-composites combinations, among others. Presently, the transportation sector is looking for lighter materials that allow for reducing fuel consumption and the environmental footprint. Aluminum and magnesium alloys, as well as composites and polymers, are considered strategic for such purposes, and their joining in metal-metal or hybrid assemblies has been explored to develop lightweight components. These multimaterial assemblies are often exposed to aggressive environments in which moisture and aggressive species are present. Under these conditions corrosion phenomena are a major source of material failures. Depending on the nature of the metals and nonmetals and of the joining process, the mechanism and extent of corrosion can vary significantly. Thus, it is essential to understand the impact of corrosion in joined materials and to know which counter-measures can be adopted to mitigate corrosion events in the system of concern. This chapter aims at reviewing the latest results of studies focused in corrosion issues in the joining of lightweight materials. It describes the most common corrosion phenomena observed in joined materials, and it emphasizes corrosion issues in assemblies that combine different metals and that combine metals with nonmetals. Moreover, it overviews the state-of-the-art in corrosion protection strategies that can be applied and, finally, it overlooks the future trends.