STP1210

    Slow Strain Rate Testing of Precracked Titanium Alloys in Salt Water and Inert Environments

    Published: Jan 1993


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    Abstract

    The stress corrosion cracking (SCC) propagation kinetics of fatigue-precracked Ti-6Al-4V (an α-β alloy) and Ti-15V-3Al-3Cr-3Sn (a β-α alloy) were studied in neutral 3.5% NaCl solution and in inert environments. The slow strain rate method was used instead of the constant load method. This was pursued in an effort to minimize the number of specimens normally required and reduce the time required to determine the stress intensity threshold for SCC. The results were encouraging, but some anomalies in the crack growth kinetics were noted. At a relatively low extension rate, crack rates in both alloys alternated between high Stage II rates and very low rates during the test. At a higher extension rate, crack rates in the Ti-15-3 alloy behaved as previously described, whereas in the Ti-6-4 alloy crack growth remained at Stage II rates continuously above the threshold. No traces of crack arrest could be found on the fracture surfaces.

    Keywords:

    stress corrosion cracking (SCC), environmental cracking, discontinuous cracking, slow strain rate, titanium alloy


    Author Information:

    Meyn, DA
    Naval Research Laboratory, Washington, DC,

    Pao, PS
    Naval Research Laboratory, Washington, DC,


    Paper ID: STP12761S

    Committee/Subcommittee: G01.06

    DOI: 10.1520/STP12761S


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