STP631: Corrosion Fatigue Properties of Ti-6Al-6V-2Sn (STOA)

    Krupp, WE
    Group engineer, research scientist, and research scientist, Lockheed-California Company, Rye Canyon Research Laboratory, Valencia, Calif

    Ryder, JT
    Group engineer, research scientist, and research scientist, Lockheed-California Company, Rye Canyon Research Laboratory, Valencia, Calif

    Pettit, DE
    Group engineer, research scientist, and research scientist, Lockheed-California Company, Rye Canyon Research Laboratory, Valencia, Calif

    Hoeppner, DW
    Professor of Engineering, University of Missouri, Columbia, Mo

    Pages: 20    Published: Jan 1977


    Abstract

    The corrosion fatigue crack properties of Ti-6Al-6V-2Sn (STOA) were studied in room-temperature laboratory air, dry air, high-humidity air, and 3.5 percent sodium-chloride solution environments. The alloy was characterized by chemical, microstructural, tensile, and fracture-toughness properties. Corrosion fatigue tests were conducted using wedge-open load (WOL), center-cracked-through (CCT) and part-through-cracked (PTC) specimens. Frequency and environmental interactions were studied as well as the effects of orientation and stress ratio. The effect of frequency was to increase the fatigue crack growth rate as the frequency was decreased. A severe effect of frequency was noted in salt water where at 0.1 Hz, crack-growth rates increased to such a high level that failure occurred at Kmax levels significantly below the stress-corrosion cracking threshold. Fractographic studies showed no apparent cause of this unexpected phenomenon.

    Keywords:

    crack propagation, corrosion fatigue, titanium, frequency, environment


    Paper ID: STP35549S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP35549S


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