Lithium-aluminum alloys

Metallurgy. Lithium forms alloys with numerous metals. Early uses of lithium alloys were made in Germany with the production of the lead alloy, BahnmetaH (0.04% Li), which was used for bearings for railroad cars, and the aluminum alloy, Scleron. In the United States, the aluminum alloy X-2020 (4.5% Cu, 1.1% Li, 0.5% Mn, 0.2% Cd, balance Al) was introduced in 1957 for stmctural components of naval aircraft. The lower density and stmctural strength enhancement of aluminum lithium alloys compared to normal aluminum alloys make it attractive for uses in airframes. A distinct lithium—aluminum phase (Al Li) forms in the alloy which bonds tightly to the host aluminum matrix to yield about a 10% increase in the modules of elasticity of the aluminum lithium alloys produced by the main aluminum producers. The density of the alloys is about 10% less than that of other stmctural aluminum alloys. 

Fig. 11. Modulus inciease as a function of fibei volume fraction alumina fiber-reinforced aluminum—lithium alloy matrix for (a) E (elastic modulus),...

Aluminum-lead alloys, 2 314 phase transitions, 2 308t Aluminum-lithium alloys, 2 312, 313 15 134-135... 

New alloys, such as aluminum-lithium alloys for aircraft applications that will permit 7 to 10% weight reduction per aircraft. 

Webster, D., and C.G, Bennett Toughfer) Aluminum-Lithium Alloys. Adv. Mat. 

Recent encouraging results have been reported by Carter et al., who have obtained room temperature lifetimes in excess of 7000 h for encapsulated ITO/PPV/Ca devices at current densities of 60 mA/cm2.37 The polymer used was the PPV copolymer shown in Fig. 5.23, where the conjugation is interrupted by nonconjugated a -acetyloxy-/ -xylylene units. The efficiency of these devices was typically 0.02 lm/W. Devices operating at 80° C had lifetimes in excess of 1100 h. Carter et al., also reported devices based on the same emissive polymer giving efficiencies between 0.5 and 2 lm/W. These devices used a layer of conducting polymer (polyethylenedioxythiophene/polystyrene sulfonate) between the ITO and the PPV, and a sputtered aluminum/lithium alloy as the cathode. The devices... 

H. Kroninger and A. Reynolds, R-Curve Behavior of Friction Stir Welds in Aluminum-Lithium Alloy 2195, Fatigue Fract. Eng. Mater. Struct, Vol 25, 2002, p 283-290... 

Tool Region of Friction Stir Welded Aluminum Lithium Alloys, Proceedings of the First International Symposium on Friction Stir Welding, June 1999 (Thousand Oaks, CA), TWI G. Engelhard et al Orbital Friction Stir Welding of Aluminum Pipes, Proceedings of the Third International Symposium on Friction Stir Welding, Sept 2001 (Kobe, Japan), TWI... 

I. Charit, R.S. Mishra, and K.V. Jata, Superplastic Behavior of Friction Stir Processed Aluminum-Lithium Alloy, Friction Stir Welding and Processing, Nov 4—8, 2001 (Indianapolis, IN), TMS, 2001, p 225-234... 

The often used FPL etdi of an aluminum-lithium alloy bonded with polysulfone leads to interfacial (at the metal oxide/polymer interface) failure (38) which is a surprisingly uncommon type of failure. The results leading to this assignment are shown as XPS C Is and O Is narrow scan spectra in Figure 15. This definitive assignment of failure mode is based on the fact that one failure surfece has an oi gen photopeak similar to the pretreated adherend before bonding and the other failure surfece has an 0 gen photopeak similar to the adhesive. 

Thompson, J. J., "Exfoliation Corrosion Testing of Aluminum-Lithium Alloys," New Methods for Corrosion Testing of Aluminum Alloys, ASTM STP 1134, V. S. Agatwafa and G. M. Ugiansky, Eds., ASTM International, West Conshohocken, PA, 1992, pp. 70-81. 

Buchheit, R. G. and Stoner, G. E., "The Corrosion Behavior of the T, Al2Cu-Li Intermetallic Compound in Aqueous Environments, Aluminum-Lithium Alloys," Proceedings of the 5th International Aluminum-lithium Conference, T. H. Sanders, Jr. and E. A. Starke, Jr., Eds., 1989, pp. 1347-1356. 

COMPATABILITY WITH ADVANCED ALUMINUM-LITHIUM ALLOYS... 

New Aluminum Lithium Alloys to Reduce Aliomin um Air Frame Weight by Up to 15 Percent, Alcoa News Release,... 

In the case of aluminum-lithium alloy, the density decreases with increasing concentration of lithium when aluminum is used as liquid cathode. Consequently, the density difference decreases and may lead to the floating of metal and low current efficiencies. 

The corrosion resistance of aluminum and aluminum-lithium alloys in marine environments. In this example, electrochemical impedance spectroscopy (EIS) was used to characterize the corrosion resistance of the three orthogonal faces of aluminum and aluminum-lithium sheet material exposed to a synthetic marine environment, and the results... 

Lenard, D. R., Moores, J. G., Roberge, P. R., and Halliop, E., The Use of Electrochemical Impedance Spectroscopy to Predict the Corrosion of Aluminum-Lithium Alloys in Marine Environments, AGARD CP-565, in AGARD Conference Proceedings Corrosion Detection and Management of Advanced Airframe Materials, Hull, Canada, Canada Publication Group, 1995, pp. 8-1—8-12. 

A generation of new aluminum-lithium alloys have been developed recently for use by the aircraft and aerospace industries. These materials have relatively low densities (between about 2.5 and 2.6 g/cm ), high specific moduli (elastic modulus-specific gravity ratios), and excellent fatigue and low-temperature toughness properties. Furthermore, some of them may be precipitation hardened. However, these materials are more costly to manufacture than the conventional aluminum alloys because special processing techniques are required as a result of lithium s chemical reactivity. 

Anon. (1998). Aluminum-Lithium Alloys. Light Metal Age 56(1 -2), 102-105. 

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