This project aims to develop the theory behind why micro alloying contributes to the formation of surface film properties. The exemplar is a prototype magnesium-lithium (Mg-Li) base alloy, with high specific-strength and corrosion resistance. This project will lead to the development of a new processable ultra-lightweight, corrosion resistant Mg-Li alloy family that is stronger than the prototype alloy, and with, at least, comparable ductility and corrosion resistance. Not only will the outcomes of the work be a fundamental advance to the fields of metallurgy and corrosion science, they will lead to the identification of an optimised compositional window for creating our second generation Mg-Li alloy family capable of being manufactured into ultra-lightweight, corrosion resistant metal products.