The Evolution of Al-Li Base Products for Aerospace and Space Applications

A technical review of the physical, mechanical, and metallurgical variables that have influenced performance of Al-Li based alloys over the last 50 years is presented. First, the historic evolution of different alloys is discussed. Then, the microstructural features responsible for different mechanical properties are identified and discussed. The role of alloying additions is discussed. The shortcomings of a 2nd generation Al-Li alloys are introduced and the key alloy design principles used to overcome these are discussed. Finally, the performance parameters that play a major role in sizing several aircraft and space craft components are reviewed in a chronological perspective and compared with 3rd-generation Al-Li alloys. It is concluded that significant improvements have been made to position Al-Li alloys to enable improved performance of next generation of air and space craft.