Accession Number : ADA182524

Title :   Processing and Superplasticity in Lithium-Containing Al-Mg Alloys.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Sanchez,Benjamin W.

Report Date : MAR 1987

Pagination or Media Count : 53

Abstract : The refined microstructures and superplastic properties resulting from controlled thermomechanical processing of a aluminum magnesium lithium zirconium alloy were evaluated. The processing involved warm rolling at 300 C separately to true strains of 1.9 and 2.6. Increasing the rolling strain enhanced the superplastic ductility of the alloy at 300 C. Elongations in excess of 500 percent without cavitation, and a corresponding strain rate sensitivity coefficient of approximately 0.5, were obtained. TEM investigations of the microstructural characteristics responsible for the mechanical behavior revealed that a more uniformly refined grain structure (2-5 micrometer) evolved by continuous recrystallization in material experiencing the larger rolling strain. It was also concluded that the increase in rolling strain enhances grain refinement both preceding and concurrent with superplastic deformation. Keywords: Superplasticity, Superplastic deformation, Thermomechanical processing, Thesis.

Descriptors :   *LITHIUM ALLOYS, *ALUMINUM ALLOYS, *MAGNESIUM ALLOYS, *ROLLING(METALLURGY), GRAIN STRUCTURES(METALLURGY), MECHANICAL PROPERTIES, MICROSTRUCTURE, PLASTIC DEFORMATION, PLASTIC PROPERTIES, PROCESSING, RECRYSTALLIZATION, REFINING, SENSITIVITY, STRAIN RATE, TEMPERATURE, THERMOMECHANICS, ZIRCONIUM ALLOYS, DEFORMATION, TENSILE PROPERTIES, METASTABLE ALLOYS, PHASE STUDIES, TEST AND EVALUATION, ALUMINUM, CAVITATION, COEFFICIENTS, CONTROL, ELONGATION

Subject Categories : Fabrication Metallurgy
      Properties of Metals and Alloys
      Aircraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE