Effects of strain variations on aging response and corrosion properties of third generation Al-Li alloys

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dc.contributor.advisorKaufman, Michael J.
dc.contributor.authorWright, Ellen E.
dc.contributor.committeememberField, Robert
dc.contributor.committeememberFindley, Kip Owen
dc.contributor.committeememberBourne, Gerald
dc.contributor.committeememberBerger, John R.
dc.contributor.committeememberWeber, Gary Robert
dc.date.accessioned2016-10-04T15:59:11Z
dc.date.accessioned2022-02-03T12:56:17Z
dc.date.available2016-10-04T15:59:11Z
dc.date.available2022-02-03T12:56:17Z
dc.date.issued2016
dc.descriptionIncludes bibliographical references.
dc.description2016 Fall.
dc.description.abstractDue to their high specific strength (strength/density) and specific stiffness (elastic modulus/density), Al-Li alloys are attractive alloys for structural aircraft applications. To produce contoured aircraft components from Al-Li wrought products, stretch forming prior to aging is a common manufacturing technique. The effects of different amounts of tensile straining (0-9%) on the mechanical, microstructural, and corrosion properties of two third generation Al-Li alloys (2099 and 2196) were investigated. In addition to typical characterization techniques, electron backscatter diffraction (EBSD), 2D micro-digital image correlation (DIC), and scanning Kelvin probe force microscopy (SKPFM) were used to examine site-specific effects of orientation, micro-strain evolution during straining, and surface potential on corrosion, respectively. Tapping mode atomic force microscopy (AFM) was also performed to study galvanic corrosion in artificial seawater (3.5% NaCl) as it occurred in-situ. There was evidence of intergranular corrosion for 0% strain conditions, but the dominant form of corrosion was localized pitting for all specimens except Alloy 2196 strained 0%. Pitting initiated at grain boundaries and triple points. In many cases, pitting extended into particular grains and was elongated in the extrusion direction. Regions of high micro-strain preferentially corroded, and large, recrystallized grains in mostly unrecrystallized microstructures were detrimental to corrosion properties. Recommendations for improved thermomechanical processing and/or alloying to promote corrosion resistance of 2XXX series Al-Li alloys were investigated.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierT 8151
dc.identifier.urihttps://hdl.handle.net/11124/170450
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2010-2019 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectatomic force microscopy
dc.subjectdigital image correlation
dc.subjectstretch forming
dc.subjectcorrosion
dc.subjectaluminum-lithium
dc.subjectstrain
dc.titleEffects of strain variations on aging response and corrosion properties of third generation Al-Li alloys
dc.typeText
dspace.entity.typePublication
thesis.degree.disciplineMetallurgical and Materials Engineering
thesis.degree.grantorColorado School of Mines
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)
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