Accession Number : ADP005923

Title :   The Microstructure and Properties of Aluminum-Lithium Alloys,

Corporate Author : VIRGINIA UNIV CHARLOTTESVILLE SCHOOL OF ENGINEERING AND APPLIED SCIENCE

Personal Author(s) : Starke, Edgar A., Jr. ; Quist, William E.

Report Date : AUG 1989

Pagination or Media Count : 23

Abstract : The advantages to be gained by weight reduction of aerospace structures have encouraged the aluminum industry to develop a family of aluminum alloys which contain lithium as one of the alloying elements. When alloyed with aluminum, lithium can reduce the density by approximately three percent and increase the elastic modulus by six percent for every weight percent added. A new series of aluminum alloys, typified by 2090, 2091, 8090, and 8091, have been developed and are currently being produced in commercial quantities. These alloys have densities between 7% and 10% lower than the conventional alloy 7075 with correspondingly higher stiffness. Although a combined set of specific properties of the (Aluminum-Lithium-X) alloys often exceeds those of the conventional aluminum materials used in aerospace, these properties seem to be much more sensitive to processing parameters. The strong processing-property relationship is associated with sharp crystallographic textures that are developed during primary processing and very complex precipitate microstructures whose distributions are sensitive to quench rates and degree of deformation prior to aging. This paper describes the processing-microstructure-property relationships of the new Al-Li-X alloys and focuses on strength, ductility, fracture toughness, fatigue and stress corrosion properties. Keywords: Symposia, Metallurgy, Microstructure, Alloys, Mechanical properties. (JG)

Descriptors :   *MICROSTRUCTURE, *ALLOYS, *MECHANICAL PROPERTIES, *ALUMINUM, *LITHIUM, SYMPOSIA, METALLURGY, MODULUS OF ELASTICITY, AEROSPACE INDUSTRY, FRANCE, QUENCHING, DEFORMATION, AGING(MATERIALS), STRENGTH(MECHANICS), DUCTILITY, FRACTURE(MECHANICS), FATIGUE(MECHANICS), STRESSES, CORROSION.

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE