Structure-property-process relations of solid-state additively manufactured aerospace aluminum alloys

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dc.contributor Rodriguez, Rogie I.
dc.contributor Brewer, Luke N.
dc.contributor Kasemer, Matthew
dc.contributor.advisor Allison, Paul G.
dc.contributor.advisor Jordon, J. Brian Mason, Craig Joseph Taylor 2020-09-30T17:24:46Z 2020-09-30T17:24:46Z 2020
dc.identifier.other u0015_0000001_0003605
dc.identifier.other Mason_alatus_0004D_14170
dc.description Electronic Thesis or Dissertation
dc.description.abstract Additive manufacturing processes provide new avenues to additively repair or manufacture complex aerospace components. There has been limited success in additively manufacturing aluminum alloys and aluminum metal matrix composites that are susceptible to hot-cracking. Recently, the development of a transformative solid-state additive manufacturing process, Additive Friction Stir-Deposition (AFS-D), incorporated the benefits of additive manufacturing and severe plastic deformation processes that provided a new path to fabricate fully-dense aluminum alloy and aluminum metal matrix composite structures. In this work, the microstructural evolution and mechanical response of an Al-Cu-Mg metal matrix composite (MMC) containing 20 weight percent Al2O3 and an AA7050 isogrid structure was additively manufactured through the AFS-D process. Microstructural characterization of the tempered and overaged Al-MMC employed optical microscopy, Scanning Electron Microscopy, and Electron Backscatter Diffraction. Additionally, to quantify the mechanical response of the tempered and overaged Al-MMC, quasi-static tensile experiments were conducted in the longitudinal and transverse orientation. Dynamic tensile testing was performed on the tempered and overaged AFS-D Al-Cu-Mg material in the transverse orientation using a Split-Hopkinson pressure bar. The resulting microstructural and mechanical analysis was captured via the internal state variable (ISV) plasticity damage model. The model is consistent with continuum level kinematics, kinetics, and thermodynamics. The following research provides a foundation for rapidly additively manufacture large MMC structures through AFS-D. This study produced a fully dense AA7050 isogrid structure was manufactured without the need for additional alloying elements. Three sections of the component that exhibit differing thermomechanical processing history were evaluated for the resulting microstructure and mechanical response. The microstructural characterization of the as-deposited AA7050 employed TEM, SEM, and EBSD. The as-deposited AA7050 exhibited a refinement of the constituent particles and grains within the microstructure. Additionally, to quantify the mechanical response of the as-deposited AA7050, quasi-static tensile and high rate tensile experiments were conducted. The Internal-State Variable Plasticity model was successfully modified to be able to capture material anisotropy as a function of precipitate free zones and secondary phases size within the grain.
dc.format.extent 157 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Mechanical engineering
dc.title Structure-property-process relations of solid-state additively manufactured aerospace aluminum alloys
dc.type thesis
dc.type text University of Alabama. Department of Mechanical Engineering Mechanical Engineering The University of Alabama doctoral Ph.D.

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