Chapter 11 - Aluminium Lithium Alloys

Abstract

In recent years, the utilization of aluminium–lithium alloys has increased as aerospace manufacturers have aimed to improve both performance and fuel efficiency. While aluminium–lithium alloys (first- and second-generation alloys) have been studied for over 50 years, it was only recently that the third generation of these alloys found widespread use in the aerospace industry. Historically, first- and second-generation alloys encounter many issues, which will be discussed. Through extensive research efforts the third generation of aluminium–lithium alloys were able to overcome many of the systemic issues that plagued early aluminium–lithium alloys. This was accomplished by not only optimizing compositional and processing controls, but through a better understanding of key metallurgical concepts, such as precipitate characterization. In this section, the key metallurgical concepts pertinent to manufacturing aluminium–lithium alloys, including the physical metallurgy (precipitates, effects of minor alloying elements, texture effects, etc.), important processing steps (casting, hot forming, etc.), and the main strengthening mechanisms in these alloys will be reviewed.