Analysis of grain refinement and superplasticity in aluminum-magnesium alloys
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Authors
Abou-Salama, Ahmed Ahmed
Subjects
Superplasticity
Aluminum Magnesium Alloys
Thermomechanical Processing
Microstructural Evolution
Continuous Recrystallization
Microstructural Instability
Grain Growth
Aluminum Magnesium Alloys
Thermomechanical Processing
Microstructural Evolution
Continuous Recrystallization
Microstructural Instability
Grain Growth
Advisors
McNelley, Terry R.
Date of Issue
1987-12
Date
Publisher
Language
en_US
Abstract
Previous research had demonstrated superplastic behavior in aluminum-magnesium
alloys of high magnesium content to result from deformation processing to
an initially non-recrystallized condition. Analysis here of those data has demonstrated
that such a result may be understood in terms of constitutive equations
developed for fine-grained materials and that the constitutive equations are applicable
to materials achieving grain boundary misorientations in the range of only 2°
to 7° by a process of continuous recrystallization. The constitutive equations provide
a basis for analysis of anomalous temperature dependence of the strength and
of the activation energy for plastic deformation seen as well in this work. A study
of the separate effects of processing variables has lead to a model for continuous
recrystallization during deformation processing. This model considers recovery of
dislocations to sub-boundaries to be the critical step in this process. Application
of this model to development of advanced aluminum alloys for air frame structural applications will result in increased weight savings by such processing methods.
Type
Thesis
Description
Series/Report No
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NPS Report Number
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Format
166 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.