Advanced characterization of the oxidation behavior of grain refined NiAl

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dc.contributor Thompson, Gregory B.
dc.contributor Allison, Paul Galon
dc.contributor Brewer, Luke N.
dc.contributor Amaro, Robert L.
dc.contributor Foley, Robin D.
dc.contributor.advisor Weaver, Mark Lovell White, Rachel Ellen
dc.contributor.other University of Alabama Tuscaloosa 2019-08-01T14:24:11Z 2019-08-01T14:24:11Z 2019
dc.identifier.other u0015_0000001_0003328
dc.identifier.other White_alatus_0004D_13836
dc.description Electronic Thesis or Dissertation en_US
dc.description.abstract Reactive element doped β-NiAl is one of the most oxidation resistant materials available for high temperature use. It has been extensively studied to create the most adherent, slow growing, and passive layer possible. One recent area of interest is grain refinement, whereby the reduced metal grain size improves mechanical properties, transports reacting elements rapidly to the oxidizing surface, and facilitates the growth of a more adherent scale. This research focused on the effect of substrate grain refinement on the microstructure of its thermally grown oxide, in comparison to the oxide grown on extruded and single crystal NiAl alloys. The oxidation behavior of grain refined materials produced by via sputter deposition, ball milling, and cryomilling was found to vary significantly. Sputter deposition was shown to significantly increase the parabolic steady state oxidation rate constant, while decreasing the length of transient oxidation. Ball milling did not result in an increase in oxidation rate, but did show increased interfacial void formation as a result of the Al2O3 dispersions incorporated during the milling process. Last, cryomilling resulted in an increase in steady state oxidation rate and increased interfacial void formation that was correlated to AlN dispersions incorporated during milling. All three grain refinement methods were found to decrease the oxide grain size approximately three-fold in comparison with the oxide grown on extruded NiAl, though a consistent relationship between oxide grain size and steady state oxidation rate was not observed. This suggests that microstructural features other than substrate and oxide grain size dominate the oxidation behavior. en_US
dc.format.extent 107 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. en_US
dc.subject Materials science
dc.title Advanced characterization of the oxidation behavior of grain refined NiAl en_US
dc.type thesis
dc.type text University of Alabama. Department of Metallurgical and Materials Engineering Metallurgical/Materials Engineering The University of Alabama doctoral Ph.D.

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