Effect of Processing Path on Microstructure and Mechanical Properties of a Low Carbon, Low Alloy Advanced High Strength Steel

dc.contributorWeaver, Mark
dc.contributorDavami, Keivan
dc.contributor.advisorKumar, Nilesh
dc.contributor.authorRay, Katherine
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.date.accessioned2022-09-28T14:55:20Z
dc.date.available2022-09-28T14:55:20Z
dc.date.issued2022
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractTo address the issue of safety, reliability, and greenhouse gas emissions, there is a need for stronger, tougher, and yet cheaper material. In response to this requirement, several variants of advanced high strength steels (AHSS) have been developed with the latest focus on 3rd generation AHSS. In this work, microstructural evolution and mechanical properties of an automotive grade low carbon, low alloy steel under air-cooled, water-quenched, and tempered conditions have been studied. The microstructural characterization has been carried out using an optical microscope, scanning electron microscope, energy-dispersive spectroscope, and electron backscattered diffraction tools. Mechanical properties were determined by subjecting the steel samples to quasi-static uniaxial tensile testing at room-temperature. The microstructure of the steel in air-cooled condition was a mixture of ferrite, MA microconstituents, and cementite. In water-quenched condition, the microstructure mostly consisted of martensitic lath with a very small fraction of retained austenite and carbides (probably due to auto-tempering). In tempered state, the steel sample comprised of tempered martensite and (probably metastable) carbides. A significant increase in yield strength, YS, (1010 MPa) and ultimate tensile strength, UTS, (1109 MPa) was noted in water-quenched condition in comparison with the YS of 426 MPa and UTS of 612 MPa in air-cooled condition. The total elongation (TE) in air-cooled and water-quenched conditions was 33.5% and 21.7%, respectively. However, the majority of the plastic deformation in water-quenched state was non-uniform in nature. The mechanical properties and plastic deformation behavior of the steel in tempered condition was similar to that in water-quenched condition. Fractography revealed the scale and nature of fractographic features associated with the fractured surface to be dependent on the processing conditions. In this work, a strong influence of processing on microstructural evolution and mechanical properties were noted.en_US
dc.format.mediumelectronic
dc.format.mimetypeapplication/pdf
dc.identifier.otherhttp://purl.lib.ua.edu/186544
dc.identifier.otheru0015_0000001_0004503
dc.identifier.otherRay_alatus_0004M_14943
dc.identifier.urihttps://ir.ua.edu/handle/123456789/9530
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.subjectAdvanced high strength steel
dc.subjectMA Microconstituent
dc.subjectmartensite
dc.subjectprocessing
dc.titleEffect of Processing Path on Microstructure and Mechanical Properties of a Low Carbon, Low Alloy Advanced High Strength Steelen_US
dc.typethesis
dc.typetext
etdms.degree.departmentUniversity of Alabama. Department of Metallurgical and Materials Engineering
etdms.degree.disciplineMaterials Science
etdms.degree.grantorThe University of Alabama
etdms.degree.levelmaster's
etdms.degree.nameM.S.
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