STP675

    On the Process of Subsurface Fatigue Crack Initiation in Ti-6Al-4V

    Published: Jan 1979


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    Abstract

    The process of subsurface crack initiation in Ti-6AI-4V has been investigated in some detail. At low stress amplitudes, slip occurs primarily on prism planes and is blocked at α-β interfaces. The piled-up dislocations induce slip in the β-phase under cyclic loading which can lead to the formation of a Cottrell cleavage knife and thereby provide a site for subsurface crack initiation. At high stress amplitudes, pyramidal slip becomes operative and as a consequence a more compatible type of plastic deformation between the two phases can develop. Under these circumstances the tendency for subsurface crack initiation may be reduced.

    Keywords:

    fatigue, electron microscopy, dislocations, titanium alloys


    Author Information:

    Ruppen, J
    Graduate assistant, post doctoral research fellow, and professor, Institute of Materials Science, University of Connecticut, Storrs, Conn.

    Bhowal, P
    Graduate assistant, post doctoral research fellow, and professor, Institute of Materials Science, University of Connecticut, Storrs, Conn.

    Eylon, D
    University of Cincinnati, Cincinnati, Ohio

    McEvily, AJ
    Graduate assistant, post doctoral research fellow, and professor, Institute of Materials Science, University of Connecticut, Storrs, Conn.


    Paper ID: STP35884S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP35884S


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