Aluminium-lithium alloys are a new advanced material which is lighter than other alloys because of its low density. “As an example, every one per cent of lithium in the alloy reduces the density by three per cent,” says Phillip Morton, Director Marketing Communication for Alcoa.
Aluminium-lithium also makes the product stiffer with a higher modulus of elasticity, which makes it particularly suited to aeronautics. In addition, it is fatigue crack resistant, presents more resistance to corrosion and reduces the need for maintenance. “It is ideal for a structure such as the floor of the A380,” says Phillip Morton.
Alcoa is now involved in a research and development initiative to reduce even further the weight of the alloy and improve its qualities for the new A350.
“This is part of our integrated effort to reduce the weight and cost of advanced aerospace metallics,” explains Phillip Morton. “We have also added a third objective, whichic is to improve the maintainability of our product.”
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ALUMINIUM-LITHIUM ALLOY This alloy, normally only used in the aviation industry (most notably the new AIRBUS A 380), is made of lithium, aluminum, titanium, zirconium, chrome-silicium, zinc and manganese. Lithium within the alloy provides improved resistance and elastic modulus among other characteristics, but paradoxically it also reduces density. In fact, the density of this exceptional material is 2.6 while titanium is 4.9. Aluminum-Lithium was also selected from the aluminum alloys because of its high resistance to corrosion.
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Aluminum - Lithium Alloys/////
