Influence of heating temperature and holding time on the formation sequence of iron aluminides at the interface of Fe/Al coatings

Abstract Fe/Al coatings designed with different compositions were fabricated by cold spray. The effects of heat treatment on the formation of iron aluminides, such as FeAl, Fe3Al and Fe2Al5, at the Fe/Al interface were investigated. The formation sequence of iron aluminides was strongly influenced by heating temperature and the holding time. Enthalpy calculation method was used to explain the formation sequence of iron aluminides, as a supplement to Fe/Al binary phase diagram. By combining these two methods, the process of diffusion and interfacial reactions can be clarified. As a result, the heat treatment schedule can be optimized to regulate the formation sequence of iron aluminides formed at the interface, which will help inhibit the brittleness and improve the mechanical properties of Fe/Al coatings.