About Aluminides

Aluminide Anion

Aluminides are compounds containing aluminum and one or more electropositive elements. Due to its unique properties related to its place in group three of the periodic table, aluminum can bond with metals differently than other metals, forming intermetallic compounds with properties between a metallic alloy and an ionic compound.

Magnesium aluminide is an intermetallic compound of magnesium and aluminium. This compound has two common phases, beta phase magnesium aluminide (Mg2Al3) and gamma phase magnesium aluminide (Mg17Al12), which both have cubic crystal structures. Magnesium aluminides are important constituents of aluminium-magnesium and magnesium-aluminum alloys. Magnesium aluminide has been investigated for use as a reactant to produce metal hydrides in hydrogen storage technology.

Titanium aluminide is lightweight and resistant to oxidation and heat, however it suffers from low ductility. Titanium aluminide has three major intermetallic forms: gamma (TiAl) and two alpha forms, Ti3Al and TiAl3. Among the three, gamma TiAl has received the most interest and found to have the most applications due to its excellent mechanical properties and resistance to oxidation and corrosion at elevated temperatures. These properties make it a possible for TiAl based alloys to replace much more dense “superalloys” in some parts of aircraft engines, such as turbine and compressor blades. This simple substitution can substantially increase the thrust-to-weight ratio in aircraft engines.