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Effect of nickel content on the crystallization behavior in nanocrystallin (Co_(1-x)Ni_x)_88Zr_7B_4Cu1 soft magnetic alloys

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dc.contributorThompson, Gregory B.
dc.contributorChopra, Nitin
dc.contributorMankey, Gary J.
dc.contributor.advisorThompson, Gregory B.
dc.contributor.authorHornbuckle, Billy Chad
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.date.accessioned2017-03-01T16:25:31Z
dc.date.available2017-03-01T16:25:31Z
dc.date.issued2012
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractA series of (Co_(1-x)Ni_x)_88Zr_7B_4Cu1 soft magnetic alloys, where X was varied from 0 to 1, were fabricated by a melt spinning process into thin ribbons of the material. This process was followed by an isothermal anneal to produce a nanocomposite alloy, i.e. nanocrystalline grains in a residual amorphous matrix. The alloy series was designed to investigate crystallization kinetics and limits to the compositional regime where a nanocomposite could be formed. The primary and secondary crystallization temperatures of each alloy were determined using Differential Scanning Calorimetry (DSC) from which the crystallization activation energies were calculated using the Kissinger Method. When X exceeded 0.75, the as-spun ribbons exhibited partial crystallization, resulting in reduced exothermic crystallization peaks. For lower Ni contents, the ribbons were amorphous in the as-spun state. The activation energy for crystallization decreased with increasing Ni content. Transmission Electron Microscopy (TEM) and Atom Probe Tomography (APT) revealed fine nanocrystallite and boron segregation to the grain boundaries with increasing Ni content. The previously suspected use of Cu clustering, which can act as heterogeneous nucleation sites, showed no clear correlation with observed spatial location of the crystallites. Chemical partitioning between species in the as-spun and primary crystallization heat treatments were correlated to the resulting changes in magnetic properties. As Ni content increased, the saturation magnetization and normalized magnetization for these samples decreased accordingly.en_US
dc.format.extent59 p.
dc.format.mediumelectronic
dc.format.mimetypeapplication/pdf
dc.identifier.otheru0015_0000001_0000880
dc.identifier.otherHornbuckle_alatus_0004M_11056
dc.identifier.urihttps://ir.ua.edu/handle/123456789/1379
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.titleEffect of nickel content on the crystallization behavior in nanocrystallin (Co_(1-x)Ni_x)_88Zr_7B_4Cu1 soft magnetic alloysen_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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