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Hyperbaric growth of carbon fibers by laser chemical vapor deposition

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dc.contributorKung, Patrick
dc.contributorWang, Ruigang
dc.contributor.advisorThompson, Gregory B.
dc.contributor.authorRife, Justin Lee
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.date.accessioned2019-08-01T14:24:24Z
dc.date.available2019-08-01T14:24:24Z
dc.date.issued2019
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractLaser Chemical Vapor Deposition (LCVD) is a promising new processing technique by which freestanding structures, such as fibers, can be deposited. The deposition of carbon fibers by use of ethylene as a precursor gas can be easily achieved and has been investigated as a way to complement or even replace current carbon fiber production techniques. The properties of carbon fibers deposited from ethylene via LCVD have been investigated for low precursor pressures thus far. However, deposition rates for low precursor pressures are limited and rates that are orders of magnitude faster can be achieved by use of higher precursor pressures. No detailed studies on properties of fibers processed at these higher pressures have been conducted. This thesis fills this knowledge gap by exploring the relationships between processing conditions, growth behavior, microstructure and mechanical properties of carbon fibers deposited from ethylene at hyperbaric pressures. It is found that the fiber growth rates are limited by surface reaction kinetics at low temperatures, while they are mass transport limited or gas phase nucleation limited at high temperatures. When grown under mass transport limited conditions, fibers exhibit drastic changes in morphology and microstructure. The tensile strengths of the carbon fibers grown by LCVD are generally found to be poor due to the nature of graphitic carbon deposits. However, the Weibull modulus among the LCVD grown carbon fibers is found to be high. Trends in mechanical properties with processing conditions and microstructure are observed.en_US
dc.format.extent93 p.
dc.format.mediumelectronic
dc.format.mimetypeapplication/pdf
dc.identifier.otheru0015_0000001_0003347
dc.identifier.otherRife_alatus_0004M_13831
dc.identifier.urihttp://ir.ua.edu/handle/123456789/6160
dc.languageEnglish
dc.language.isoen_US
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.subjectMaterials science
dc.subjectMechanical engineering
dc.titleHyperbaric growth of carbon fibers by laser chemical vapor depositionen_US
dc.typethesis
dc.typetext
etdms.degree.departmentUniversity of Alabama. Department of Metallurgical and Materials Engineering
etdms.degree.disciplineMetallurgical/Materials Engineering
etdms.degree.grantorThe University of Alabama
etdms.degree.levelmaster's
etdms.degree.nameM.S.

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