<mods:mods xmlns:mods="http://www.loc.gov/mods/v3" xmlns:METS="http://www.loc.gov/METS/" xmlns:fits="http://hul.harvard.edu/ois/xml/ns/fits/fits_output" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:IR="http://dl.lib.brown.edu/md/irdata" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:rights="http://cosimo.stanford.edu/sdr/metsrights/" ID="etd160">
     <mods:titleInfo>
      <mods:title>Fracture in Single and Bicrystals of Zinc: Experiments and Computational Modeling</mods:title>
     </mods:titleInfo>
     <mods:name type="personal">
      <mods:namePart>Catoor, Dhiraj</mods:namePart>
      <mods:role>
       <mods:roleTerm type="text">creator</mods:roleTerm>
      </mods:role>
     </mods:name>
     <mods:originInfo>
      <mods:copyrightDate keyDate="yes" encoding="w3cdtf">2008</mods:copyrightDate>
     </mods:originInfo>
     <mods:physicalDescription>
      <mods:extent>xxiv, 172 p.</mods:extent>
      <mods:digitalOrigin>born digital</mods:digitalOrigin>
     </mods:physicalDescription>
     <mods:note>Thesis (Ph.D.) -- Brown University (2009)</mods:note>
     <mods:name type="personal">
      <mods:namePart>Kumar, Sharvan</mods:namePart>
      <mods:role>
       <mods:roleTerm type="text">director</mods:roleTerm>
      </mods:role>
     </mods:name>
     <mods:name type="personal">
      <mods:namePart>Bower, Allan</mods:namePart>
      <mods:role>
       <mods:roleTerm type="text">reader</mods:roleTerm>
      </mods:role>
     </mods:name>
     <mods:name type="personal">
      <mods:namePart>Briant, Clyde</mods:namePart>
      <mods:role>
       <mods:roleTerm type="text">reader</mods:roleTerm>
      </mods:role>
     </mods:name>
     <mods:name type="personal">
      <mods:namePart>Curtin, William</mods:namePart>
      <mods:role>
       <mods:roleTerm type="text">reader</mods:roleTerm>
      </mods:role>
     </mods:name>
     <mods:name type="corporate">
      <mods:namePart>Brown University. Division of Engineering. Materials Science Engineering</mods:namePart>
      <mods:role>
       <mods:roleTerm type="text">sponsor</mods:roleTerm>
      </mods:role>
     </mods:name>
     <mods:genre authority="aat">theses</mods:genre>
     <mods:abstract> In polycrystalline materials where transgranular cleavage is the preferred fracture mode, the crystallographic misorientation of fracture planes across grain boundaries can
      provide resistance to crack growth, though the details of its contribution to fracture resistance is not fully understood. Recent studies on diverse structural materials such as steels, aluminum
      alloys and intermetallics show a correlation between an increased fracture resistance and the twist component of grain misorientation; however the lack of control over the degree and type of
      misorientation has precluded a systematic analysis of the problem. In this dessertation, this phenomenon is investigated through in situ crack propagation experiments across grain boundaries of
      controlled twist misorientation in bicrystals of zinc. The lack of comprehensive understanding of the micromechanisms of fracture in single crystals of zinc required in situ experiments to be
      initially conducted to investigate crack propagation on the basal planes. In single crystals, quasistatic loading caused crack propagation in short bursts of dynamic crack extension followed by
      periods of arrests. In situ observations confirmed re-nucleation of micro-cracks on parallel basal planes and failure of the linking ligaments and crack-growth resistance due to pre-existing
      twins in the crack path. The crack growth response, load-displacement behavior and fracture surface topography were all found to be dependent on the crack propagation direction on the basal
      plane. Significant resistance to crack propagation was observed in bicrystals at the grain boundaries through extrinsic toughening mechanisms that come into play upon crack stagnation at the
      boundary. Strong dependence of the load displacement behavior and crack propagation resistance on the twist angle was observed. Several accommodation mechanisms such as twinning in the
      crack-wake, strain localization and slip band blocking contribute to fracture resistance and suppress crack propagation across grain boundary at higher twist angles. Three-dimensional finite
      element models incorporating crystal plasticity are used to explain the micromechanisms of crack propagation, orientation-dependent crack growth response and fracture surface topography in
      single crystals, and qualitatively capture several features of crack-grain boundary interaction in bicrystals.</mods:abstract>
     <mods:subject authority="local">
      <mods:topic>Fracture</mods:topic>
     </mods:subject>
     <mods:subject authority="local">
      <mods:topic>FEM</mods:topic>
     </mods:subject>
     <mods:subject authority="local">
      <mods:topic>Single Crystals</mods:topic>
     </mods:subject>
     <mods:subject authority="local">
      <mods:topic>Bicrystals</mods:topic>
     </mods:subject>
     <mods:subject authority="local">
      <mods:topic>Crack Growth</mods:topic>
     </mods:subject>
     <mods:subject authority="local">
      <mods:topic>Grain Boundary Resistance to Fracture,</mods:topic>
     </mods:subject>
     <mods:subject authority="FAST" authorityURI="http://id.worldcat.org/fast" valueURI="http://id.worldcat.org/fast/1184377"><mods:topic>Zinc</mods:topic></mods:subject><mods:recordInfo>
      <mods:recordContentSource authority="marcorg">RPB</mods:recordContentSource>
      <mods:recordCreationDate encoding="iso8601">20091218</mods:recordCreationDate>
     </mods:recordInfo>
    <mods:language><mods:languageTerm type="code" authority="iso639-2b">eng</mods:languageTerm><mods:languageTerm type="text">English</mods:languageTerm></mods:language><mods:identifier type="doi">10.7301/Z0222S6B</mods:identifier><mods:accessCondition type="rights statement" xlink:href="http://rightsstatements.org/vocab/InC/1.0/">In Copyright</mods:accessCondition><mods:accessCondition type="restriction on access">Collection is open for research.</mods:accessCondition><mods:typeOfResource authority="primo">dissertations</mods:typeOfResource></mods:mods>