Characterization of the evolution of 2219-T87 aluminum as a function of the self-reacting friction stir welding process

dc.contributorAmaro, Robert
dc.contributorMcKeighan, Pete
dc.contributorWeaver, Mark
dc.contributor.advisorDaniewicz, Steve
dc.contributor.authorAnderson, Kathryn
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractThe self-reacting friction stir welding (SR-FSW) process is a primary method used by NASA to construct the Space Launch System (SLS) vehicle. This method uses large scale shear to plastically deform and mechanically mix base materials. This solid-state process causes the fabricated material to reach a temperature below the melting point, and as such, there are lower residual stresses and less warping than that observed in traditional fusion welding processes. The process parameters responsible for heat generation in the SR-FSW process include: the tool rotational speed, the tool translational speed, the crown plunge force, and the root/pin reaction force. Optimization of these process parameters is required to produce sound welded joints with the appropriate microstructural constituents. This work characterizes the effect of SR-FSW on AA2219-T87. Specifically, the material’s microhardness, strength, and θ-phase evolution are studied as a function of time and temperature. These data sets are compared to the microhardness in the friction stir weld stir zone, thermo-mechanically affected zone (TMAZ), heat affected zone (HAZ), and base material. Additionally, residual stresses produced as a function of the friction stir welding process are quantified. Furthermore, fatigue crack growth rate data and plane-strain fracture toughness data of the welded material are compared to that of the base material. Finally, all data collected is used to calibrate a tool that determines the relative contribution from various strengthening mechanisms to the overall strength of the weld.en_US
dc.format.extent78 p.
dc.publisherUniversity of Alabama Libraries
dc.relation.hasversionborn digital
dc.relation.ispartofThe University of Alabama Electronic Theses and Dissertations
dc.relation.ispartofThe University of Alabama Libraries Digital Collections
dc.rightsAll rights reserved by the author unless otherwise indicated.en_US
dc.subjectMechanical engineering
dc.titleCharacterization of the evolution of 2219-T87 aluminum as a function of the self-reacting friction stir welding processen_US
dc.typetext of Alabama. Department of Mechanical Engineering Engineering University of Alabama's
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