2195 aluminium alloy

Alloy of aluminium and lithium

2195 aluminium alloy is an alloy in the wrought aluminium-copper family (2000 or 2xxx series). It is one of the Weldalite family of Aluminium–lithium alloys.^[1] It is one of the most complex grades in the 2000 series, with at least 91.9% aluminium by weight. 2195 aluminium can be alternately referred to by the UNS designation A92195.

Properties

Like most other aluminium-copper alloys, 2195 is a high-strength alloy, with bad workability, and poor corrosion resistance. Being highly alloyed, it tends to fall on the higher strength and lower corrosion resistance side. As a wrought alloy, it is not used in casting. It can be welded, particularly by friction stir welding, and is fracture resistant at cryogenic temperatures.^[1]

Applications

The high strength to weight ratio of this alloy has resulted in its aerospace applications such as the Space Shuttle Super Lightweight external tank.^[1] It is 30 % stronger and 5 % less dense than the 2219 alloy used in the original Space Shuttle external tank.^[1]

2195 is used for the propellant tanks of the Falcon 9 Full Thrust orbital launcher,^[2]^[3] and for the new ULA Vulcan first stage.^{[citation needed]}

Chemical Composition

The alloy composition of 2195 aluminium is:^[4]^[5]

Aluminium: 91.9 to 94.9%
Copper: 3.7 to 4.3%
Lithium: 0.8 to 1.2%
Magnesium: 0.25 to 0.8%
Silver: 0.25 to 0.6%
Zirconium: 0.08 to 0.16%
Iron: 0.15% max
Silicon: 0.12% max
Titanium: 0.1% max
Zinc: 0.25% max
Residuals: 0.15% max

References

^ ^a ^b ^c ^d Super Lightweight External Tank, NASA, retrieved 12 Dec 2013.
^ "How Light Metals Help SpaceX Land Falcon 9 Rockets with Astonishing Accuracy". Light Metal Age. 26 April 2019. Archived from the original on 28 August 2023. Retrieved 9 May 2024.
^ "Falcon 9". SpaceX. 2013. Archived from the original on 24 September 2013. Retrieved 2013-12-06.
^ Häusler, Ines; Schwarze, Christian; Bilal, Muhammad; Ramirez, Daniela; Hetaba, Walid; Kamachali, Reza; Skrotzki, Birgit (2017). "Precipitation of T₁ and θ′ Phase in Al-4Cu-1Li-0.25Mn During Age Hardening: Microstructural Investigation and Phase-Field Simulation". Materials. 10 (2) 117. doi:10.3390/ma10020117. ISSN 1996-1944. PMC 5459132. PMID 28772481.
^ "2195 Aluminum Composition Spec". www.matweb.com. Retrieved 2024-02-18.