Grain boundary development in superplastic aluminum alloys
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Authors
McMahon, Michael Edward
Subjects
Superplastic
Aluminum
Grain Boundary
Aluminum
Grain Boundary
Advisors
McNelley, T.R.
Date of Issue
1996-12
Date
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
Superplasticity may be defined as the capability of certain polycrystalline materials to deform to extensive plastic elongations prior to failure, often without formation of a neck. Typically, superplasticity refers to tensile elongations greater than 200%, although some elongations have been reported in excess of 5000% Ref 1. While it has been suggested that bronze metals in use in ancient civilizations may have possessed superplastic properties Ref 2, most historical reviews credit the modern-day documentation of superplastic behavior to a paper published in the Journal of the Institute of Metals by G.D. Bengough in 1912 which described extensive elongations in brass Ref 3. Recognition of a stress and strain-rate relationship was first presented qualitatively in a paper by Rosenhain in 1920 which examined a near eutectic Zn- Al-Cu alloy Ref 4. Photomicrographs detailing superplastic grain structures in eutectic Sn-Pb and Bi-Pb alloys deformed to elongations of 2000% were presented in 1934 by Pearson Ref 5. This study was the first to identify an equiaxed grain morphology in the deformed regions and suggest that grain boundary migration may be involved in the deformation processes
Type
Thesis
Description
Series/Report No
Department
Mechanical Engineering
Organization
Identifiers
NPS Report Number
Sponsors
Funder
Format
xxvi, 206 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.