Fe3Al

Fe3Al is an intermetallic compound with a 3:1 iron-to-aluminum ratio, belonging to the iron–aluminum (Fe–Al) system. It is most commonly described by a DO3-type ordered cubic structure that arises from a body-centered cubic (BCC) lattice. In this phase, iron and aluminum atoms occupy distinct sublattices, whereas at higher temperatures the material tends toward a disordered A2 or partially ordered B2 state.

Synthesis and processing typically involve alloying iron and aluminum by methods such as arc melting or powder metallurgy, followed by annealing at elevated temperatures (on the order of several hundred to about 1000 degrees Celsius) to promote DO3 ordering. The ordering can be influenced by cooling rate and subsequent heat treatments.

Properties of Fe3Al include good high-temperature oxidation resistance and corrosion resistance, largely due to the protective aluminum-containing oxide that can form on the surface. The intermetallic is relatively hard and strong for an Fe–Al compound, and it can exhibit good creep resistance at elevated temperatures. However, the material is prone to brittleness at room temperature, with limited ductility under conventional conditions. Ductility can be improved modestly through controlled processing and small alloying additions (such as Mn, Cr, or Ti) or by specific thermo-mechanical treatments.

Applications are mainly in areas requiring high-temperature performance and oxidation resistance, including potential uses as high-temperature structural components, protective coatings, or diffusion barriers. Fe3Al remains a subject of ongoing research to optimize its mechanical properties and processing routes for wider structural use.

See also: iron aluminides, FeAl, DO3 phase, B2 phase, A2 phase.