STP600: Effects of Very Low Pressures on Fatigue Fracture Surface Features in Ti-6Al-4V

    Meyn, DA
    Metallurgist, Engineering Materials Division, U. S. Naval Research Laboratory, Washington, D. C.,

    Pages: 13    Published: Jan 1976


    Abstract

    The amount and quality of quasi-cleavage and possibly the crack growth rates caused by fatigue of Ti-6Al-4V in vacuum were enhanced by increasing hydrogen content and decreasing cyclic loading frequency. Precision matching studies of pseudo-striations on mating vacuum fatigue fracture surfaces lead to the tentative conclusion that these do not mark successive positions of the crack front, hence are not fatigue striations. Similar studies of quasi-cleavage areas show that tear ridges mate exactly, suggesting that such cracking proceeds by a combination of micro-cleavage crack initiation and microplastic coalescence of the micro-cracks.

    Keywords:

    fatigue (materials), fractography, titanium alloys, hydrogen embrittlement, frequencies, cleavage


    Paper ID: STP29192S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP29192S


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