Processing, microstructure and superplasticity in Al-Mg-Mn alloys
Loading...
Authors
Meyer, Chris D.
Subjects
Superplasticity
Particle stimulated nucleation
Particle stimulated nucleation
Advisors
McNelley, Terry R.
Date of Issue
1991-12
Date
December 1991
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
A thermomechanical processing (TMP) schedule developed in previous work was modified to provide for an increasing strain and strain rate with each polling pass. three alloys, Al-10mg, Al-10mg-0.2Mn, and AL-10mg-0.5mn (compositions in wt. pct.), were processed utilizing this schedule. Samples were obtained following various rolling passes for subsequent microscopy analysis. Materials in both the as-rolled condition and following 25 minutes of annealing were studied. Utilizing backscattered imaging techniques with the scanning electron microscope, the microstructural evolution of these alloys during the TMP were studied. Second phase particles were observed to precipitate on grain boundaries and deformation structures in the intermediate stages of the TMP. In addition, second phase precipitates developed on MnAl6 particles through heterogeneous nucleation in the Manganese containing alloys. Particle simulation of recrystallization was observed in the latter stages of the TMP as precipitate particles coarsened. Tensile testing at 300(o)C demonstrated the superplastic response of each alloy, and showed that the addition of Manganese enhances superplastic response. Strain rate sensitivity coefficients were observed to initially decease with increasing strain, but then increased with further straining.
Type
Thesis
Description
Series/Report No
Department
Mechanical Engineering
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
62 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.