STP590: Application of the J-Integral to the Initiation of Crack Extension in a Titanium 6Al-4V Alloy

    Yoder, GR
    Metallurgists, Naval Research Laboratory, Washington, D.C.,

    Griffis, CA
    Metallurgists, Naval Research Laboratory, Washington, D.C.,

    Pages: 21    Published: Jan 1976


    Abstract

    Tests were conducted to determine JIc from resistance curves of J versus crack extension, obtained from fatigue-precracked specimens of a titanium 6Al-4V alloy. Specimens of various geometries were employed, all in three-point bending. Crack extensions were delineated by heat tinting.

    Results obtained with J computed from the equation, J = 2A/Bb, are compared to those obtained with the compliance technique, using the plane-stress solutions of Bucci et al. JIc results are compared with a valid KIc value for this material.

    The range of ratios of crack length to specimen width (a/W) is explored over which the equation J = 2A/Bb applies. The decrease in crack extension at experimental limit load (Δapmax →Δac) is examined as the ratio of specimen thickness to uncracked ligament (B/b) is increased. Variation in JIc from specimens cut from different positions through the plate thickness is also examined.

    Keywords:

    crack propagation, fractures (materials), elastic-plastic fracture, mechanical properties, crack extension, titanium alloys, compliance calibration, fracture initiation


    Paper ID: STP33939S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP33939S


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