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Wrought aluminum-lithium alloys

Dr. Dmitri Kopeliovich

Aluminum-lithium (Li) 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 33.7 lb/ft³ (540 kg/m³). 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.

Solution treatment followed by either artificial or natural aging allows considerable increasing the yield strength (3-5 times). Ductility of the alloy decreases as a result of the heat treatment.

Hardening of the alloys from this group is achieved due to precipitation of the phases Al3Li, Al2CuLi or Al2CuMg occurring during aging.

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.

Aluminum-lithium alloys are used for manufacturing aircraft structures, aerospace vehicle skins, spacecraft fuel tanks (liquid Hydrogen and oxygen).

Chemical compositions of typical aluminum-lithium alloys

Designation Li,% Cu,% Mg,% Zr,% Other,%
2020 1.3 4.5 - - Mn 0.5, Cd 0.25
2090 2.2 2.7 - 0.12 -
2091 2.0 2.1 1.5 0.10 -
8090 2.4 1.3 0.9 0.1 -
8091 2.6 1.9 0.9 0.12 -
8092 2.4 0.65 1.2 0.12 -
Weldalite 049 1.3 4.5 0.4 0.14 Ag 0.4
1420 2.0 - 5.2 0.11 -

aluminum concentration - balance

Properties of some wrought aluminum-lithium alloys

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wrought_aluminum-lithium_alloys.txt · Last modified: 2023/12/13 by dmitri_kopeliovich
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