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dc.contributor.authorAsher, Stefanie Lynnen_US
dc.date.accessioned2009-01-22T15:40:47Z
dc.date.available2009-01-22T15:40:47Z
dc.date.issued2007-11-12en_US
dc.identifier.urihttp://hdl.handle.net/1853/26499
dc.description.abstractThis research investigates the mechanism of transgranular stress corrosion cracking (TGSCC) on fuel transmission pipelines. This research proposes that in near-neutral pH environments, hydrogen can be generated by the dissociation of carbonic acid and the reaction of metal ions with bicarbonate solutions, significantly increasing the available hydrogen for diffusion into the pipeline steel. This research has shown that TGSCC of pipeline steels is possible in simple groundwater solutions containing bicarbonate ions and carbon dioxide. Microstructural characterization coupled with hydrogen permeation indicates that the level of strain in the microstructure has the most influence on hydrogen diffusivity. Hydrogen accumulation occurs preferentially in at high energy discontinuous interfaces such as inclusion interfaces. It was determined that a stress concentration is required to facilitate sufficient hydrogen accumulation in the pipeline steel in order to initiate TGSCC. It was discovered that these stress concentrations develop from inclusions falling out of the pipeline surface. Slow strain rate tests found that TGSCC occurred in a wide range of compositions and temperatures as long as near-neutral conditions were maintained. Microcracks ahead of the crack tip provide evidence of hydrogen in these cracking processes. Morphology of these microcracks indicates that cracks propagate by the coalescence of microcracks with the main crack tip. Further research findings, scientific impact, and potential future work are also discussed.en_US
dc.publisherGeorgia Institute of Technologyen_US
dc.subjectPipelinesen_US
dc.subjectCarbon dioxideen_US
dc.subjectStress corrosion crackingen_US
dc.subjectTransgranularen_US
dc.subject.lcshStress corrosion
dc.subject.lcshUnderground pipelines
dc.titleInvestigating the mechanism of transgranular stress corrosion cracking in near-neutral ph environments on buried fuel transmission pipelinesen_US
dc.typeDissertationen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentMaterials Science and Engineeringen_US
dc.description.advisorCommittee Chair: Preet M. Singh; Committee Member: Arun M. Gokhale; Committee Member: Miroslav Marek; Committee Member: Naresh N. Thadhani; Committee Member: Richard Neu; Committee Member: Thomas H. Sanders, Jr.en_US


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