STP462: Tensile and Shear-Mode Cracking of Titanium Sheet in Air and in Salt Water

    Walker, K
    Senior Research Scientist, Senior Research Engineer, and Senior Research Specialist, Lockheed California Co., Burbank, Calif.

    Pendleberry, S
    Senior Research Scientist, Senior Research Engineer, and Senior Research Specialist, Lockheed California Co., Burbank, Calif.

    McElwee, R
    Senior Research Scientist, Senior Research Engineer, and Senior Research Specialist, Lockheed California Co., Burbank, Calif.

    Pages: 7    Published: Jan 1970


    Abstract

    Crack-propagation tests were conducted using titanium alloy (Ti-6A1-4V) sheet to study the relationship between changes in salt-water cracking behavior and rotation of the crack from a tensile to a shear mode of cracking. Analysis of stress intensity versus cracking rate and examination of electron fractographs for four 16-in. wide panels of Ti-6A1-4V cycled at two stress levels showed a definite change in salt-water cracking behavior occurring at a cracking rate of approximately 260 μ in. per cycle and between the stress-intensity range of 12 ksi √in. and 17.6 ksi √in. The cracking rates in salt water and in air were found to be the same after the crack front had rotated from a tensile to a shear mode of cracking in ten specimens examined including both Ti-6A1-4V and Ti-8Al-Mo-1V.

    Keywords:

    crack propagation, salt-water environment, titanium alloys, fracture mechanics, fatigue


    Paper ID: STP32045S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP32045S


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