Understanding the fatigue and fracture mechanisms of cold spray additive repairs

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dc.contributor Barkey, Mark E.
dc.contributor Daniewicz, Steven R.
dc.contributor Genau, Amber
dc.contributor.advisor Jordon, J. Brian
dc.contributor.advisor Brewer, Luke N.
dc.contributor.author White, Benjamin
dc.date.accessioned 2019-08-01T14:23:57Z
dc.date.available 2019-08-01T14:23:57Z
dc.date.issued 2019
dc.identifier.other u0015_0000001_0003309
dc.identifier.other White_alatus_0004D_13835
dc.identifier.uri http://ir.ua.edu/handle/123456789/6122
dc.description Electronic Thesis or Dissertation
dc.description.abstract The objective of this research is to understand the underlying mechanisms associated with fatigue and fracture in additive cold spray (CS) repairs of structural components. Because of the low temperatures maintained during deposition, CS is ideal for use in additive repair applications, especially on thermally sensitive materials such as aerospace aluminum alloys. Additive repair functions as a direct alternative to scrapping and replacing the damaged component, offering huge cost savings and reduced maintenance down times. In order for structural additive repairs to be successful, the bulk material that is being used to fill the repair, the adhesion of the repair, and the repaired component must all perform well under the expected loading. While the current literature has investigated these topics, characterization of the fatigue of the freestanding material and the adhesion of CS deposits is significantly lacking. This work examines the freestanding fatigue properties of CS AA7075 and CS AA2024, and shows that they have relatively predictable fatigue performance that compares well with the wrought controls when normalized by UTS. The adhesion strength of CS deposits is of particular importance in aerospace applications where repairs that completely separate can cause foreign object damage elsewhere in the aircraft. Therefore this research seeks to understand the adhesion mechanics of CS through the use of fracture mechanics based adhesion test methods. A strong linear relationship between surface roughness and adhesion toughness was found in CS AA7075 deposits, with interfacial fracture toughness’s ranging from 1.2 to 1.9 MPa√m. Finally realistic fastener hole repairs were made in AA2024 and AA7075, which were found to perform as well or in some cases significantly better than the epoxy filled controls.
dc.format.extent 117 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 Materials Science
dc.title Understanding the fatigue and fracture mechanisms of cold spray additive repairs
dc.type thesis
dc.type text
etdms.degree.department University of Alabama. Department of Mechanical Engineering
etdms.degree.discipline Mechanical Engineering
etdms.degree.grantor The University of Alabama
etdms.degree.level doctoral
etdms.degree.name Ph.D.


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