• Login
    View Item 
    •   DSpace@RPI Home
    • Rensselaer Libraries
    • RPI Theses Online (Complete)
    • View Item
    •   DSpace@RPI Home
    • Rensselaer Libraries
    • RPI Theses Online (Complete)
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    The influence of growth rate and temperature on high cycle fatigue of directionally solidified AI-AI(sub 3)Ni eutectic alloy

    Author
    Maurer, Gernant E.
    View/Open
    178072_thesis.pdf (112.1Mb)
    Other Contributors
    Stoloff, N. S.; Duquette, D. J.; Ansell, George S.; Doremus, R. H.; Henry, Michael F.;
    Date Issued
    1976-07
    Subject
    Metallurgy
    Degree
    PhD;
    Terms of Use
    This electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.;
    Metadata
    Show full item record
    URI
    https://hdl.handle.net/20.500.13015/1909
    Abstract
    Crack initiation and propagation mechanisms were established by metallographic and fractographic examination. Crack initiation occurred at intense slip offsets which formed on the matrix surface and were supplemented by local fiber failures. Crack propagation occurred primarily in a zone of matrix material adjacent to fibers. Crack initiation and propagation in rapidly solidified Al-Al3Ni occurred along grain and colony boundaries.; Dislocation substructure-fiber interactions were studied by transmission electron microscopy. The dislocation cell size and the amount of dislocation substructure generated during high cycle fatigue was found to be a function of interfiber spacing. In 11 cm/hr material, the fiber spacing was smaller than the mutual trapping distance of the matrix dislocations and very little dislocation substructure was formed during fatigue. Extensive cellular substructure was formed in material grown at 0.5 and 3.5 cm/hr, apparently because the fiber spacing was greater than the mutual trapping distance of the dislocation. Differences in the substructure generated were used to interpret the hysteresis responses of the individual growth rates.; High-cycle fatigue tests have been conducted on specimens of the Al-Al3Ni eutectic alloy unidirectionally solidified at selected rates from 0.5 cm/hr to 1200 cm/hr. Tests were conducted in air at 298°K, 458°K, and 683°K. Room temperature fatigue lives were independent of growth rate at low solidification rates (0.5 - 30 cm/hr), but markedly improved in samples grown at 1200 cm/hr. Materials grown at 30 cm/hr exhibited fatigue lives similar to those of lower growth rate materials, despite gross misalignment due to cellular growth. At 0.5 T(sum) (458°K) and 0.75 T(sub m) (683°K), the fatigue lives of mm material grown at low solidification rates were dependent on growth rate. The dependence of fatigue life on growth rate at elevated temperatures appears to result primarily from differences in cyclic creep rates produced by varying interfiber spacings.;
    Description
    July 1976; School of Engineering
    Department
    Dept. of Materials Science and Engineering;
    Publisher
    Rensselaer Polytechnic Institute, Troy, NY
    Relationships
    Rensselaer Theses and Dissertations Online Collection;
    Access
    Restricted to current Rensselaer faculty, staff and students. Access inquiries may be directed to the Rensselaer Libraries.;
    Collections
    • RPI Theses Online (Complete)

    Browse

    All of DSpace@RPICommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    Login

    DSpace software copyright © 2002-2022  DuraSpace
    Contact Us | Send Feedback
    DSpace Express is a service operated by 
    Atmire NV