ALITHALITE ® ALLOY DEVELOPMENT AND PRODUCTION

Abstract
In 1981, the ALITHALITE ® aluminum-lithium project was established at Alcoa Laboratories, with the goal of developing low-density replacements for a variety of incumbent aerospace aluminum products. 1987 finds one of these alloys, 2090, production-ready in a range of products and a variety of tempers. Sufficient development of both sheet and extruded shapes permits the establishing of tentative mechanical property limits for several medium to highstrength targets. Thin plate, which generally is more cost-efficient than heavy-gage plate, also is being produced in several tempers. The property trade-offs arnong these various products will be discussed, as well as the limitations with regard to production capacity. A significant impediment to the production qualification of Al-Li alloys has been the difficulty in casting clean, high-quality ingot for product fabrication. Solving this problern has been crucial to the success of the project, especially in the high-strength products which alloy 2090 offers. As Al-Li moves toward production applications, a number of commercial issues are beginning to surface. Among these are rationalization of alloys and products, availability of qualification testing data, and establishing industry or producer-customer specifications. Streamlining each of these will accelerate the application of low-density alloys in aerospace structures.