锂是世界上较轻的金属元素。把锂作为合金元素加到金属铝中，就形成了铝锂合金。加入锂之后，可以降低合金的比重，增加刚度，同时仍然保持较高的强度、较好的抗腐蚀性和抗疲劳性以及适宜的延展性。因为这些特性，这种新型合金受到了航空、航天以及航海业的广泛关注。正是由于这种合金的许多优点，吸引着许多科学家对它进行研究，铝锂合金的开发事业犹如雨后春笋般迅速发展起来了。
Aluminum-lithium alloys (AL-Li) were developed primarily as direct replacements for existing aluminum alloys to reduce the weight of aircraft and aerospace structures. It has been realized that the most efficient way of doing this is to develop low density materials, since weight reduction through reduced component size often leads to low stiffness parts and reduced fatigue life. Typical components that benefit from low density alloys include structural members in airframes, aerospace vehicle skins, and liquid oxygen and hydrogen fuel tanks in spacecraft.
Aluminum producers began major development of aluminum-lithium alloys in the 1970s with the objective of introducing light weight, high stiffness aluminum alloys that could be fabricated on existing equipment and components could be handled and assembled using established techniques. Some of the most important commercial alloys in this class include 2090, 2091, 8090, and Weldalite 049 that were introduced in the 1980s. The table below shows the chemical composition of these alloys.
AA8090化学成分：
Alloy Cu Li Zr Mg Others
AA8090 1.3 2.45 0.12 0.95
铝锂合金主要为飞机和航空航天设备的减重而研制的，因此也主要应用于航空航天领域，还应用于军械和核反应堆用材，坦克穿甲弹，鱼雷和其它兵器结构件方面，此外在汽车、机器人等领域也有充分运用。
Al-Li合金已经在军用飞机、民用客机和直升飞机上使用或试用，通项金属铝锂合金主要用于机身框架、襟翼翼肋，垂直安定面、整流罩、进气道唇口、舱门、燃油箱等等。
铝锂合金具有低密度、高比强度和比刚度、优良的低温性能和耐腐蚀性以及良好的超塑性等优点.用铝锂合金取代常规的铝合金可使结构质量减轻10%~15%,刚度提高15%~20%,是一种理想的航空航天结构材料.
铝锂合金是航空技术一种新材料
新材料是航空航天技术的重要基础,航空航天技术的发展又不断对材料科学提出新的问题和要求.铝锂合金是近十几年来航空金属材料中发展较为迅速的一个领域.
