Investigation of the Microstructural and Corrosion Properties of Steels and Light Alloys

Very few metals can be found in metallic form in nature; the vast majority have to be processed from their ores at a great cost in terms of energy and money. It is therefore energetically favorable for them to reverse to their initial state. This process is commonly known as corrosion or anti-metallurgy, and great efforts are made worldwide to limit this process. According to the latest NACE estimation (2013), the global cost of corrosion is equivalent to approximately 3.4% of the global GDP (2.5 trillion USD) not considering environmental consequences or safety issues. A reduction between 15% and 35% could be realized if prevention techniques and proper precautions are used, leading to savings between USD 375 and 875 billion. Corrosion involves different sectors, such as industry, military, civilian, services, etc., particularly energy production, transport, chemical and petrochemical industries, the mechanical industry, and the drink and beverage industry. Among these sectors, most of the constituents are made of steel, which is the most-produced metal in the world (1808 million tons in 2018) or light alloys, mainly aluminum (60.1 million tons of consumption in 2018). A proper alloy design in terms of composition, heat treatment, microstructural features, etc., is mandatory to obtain the best combination of mechanical properties and corrosion resistance during operation, reducing maintenance costs and the overall impact on the global economy. In fact, microstructural features can affect both the corrosion of the material itself and the eventual production of protective layers on their surfaces. The purpose of this Special Issue is to correlate the key role of the microstructure of steels and light alloys with their corrosion properties.