ALUMINUM-LITHIUM ALLOYS

Aluminum-lithium alloys were developed for reducing weights of aircraft and aerospace structures. Aluminum-lithium alloys have decreased density because of very low density of metallic lithium . Addition of 1% of lithium results in decreasing density of the alloy by 3%. Aluminum-lithium alloys may contain also copper (Cu), magnesium (Mg), zirconium (Zr) and silver (Ag) as minor alloying elements. Aluminum-lithium alloys are heat-treatable.Aluminum-lithium alloys possess increased Modulus of Elasticity, high specific stiffness,increased fatigue strength and cryogenic strength. Alloys, containing silver, have also good weldability. Zirconium is added to aluminum-lithium alloys for controlling grain structure during heat treatment.