The aim of the class is to gain knowledge of the different levels of materials structures (atomic, crystalline, nanometric, microscopic and mesoscopic) and of the deviations from the structural perfection (defects). Knowledge of the effects of nano- and microstructure on mechanical properties of materials. Knowledge of the scientific basis for the development of micro and nanostructure. Knowledge of the relationships between nano- and microstructure, process, properties and performances of the different materials, with particular attention to metals: steels, cast irons, light alloys and high temperature alloys. The fundamental concepts needed to correlate the properties of materials to their nature, production and forming processes will be discussed, as well as notions on the classification and application problems.