STP733: Effect of Compressive Loading on Fatigue Crack Growth Rate and Striation Spacing in Type 2219-T851 Aluminum Alloy

    Albertin, L
    Senior engineer and senior engineer, Westinghouse Research and Development Center, Pittsburgh, Pa.

    Hudak, SJ
    Senior engineer and senior engineer, Westinghouse Research and Development Center, Pittsburgh, Pa.

    Pages: 15    Published: Jan 1981


    Abstract

    Macroscopic crack growth rates, da/dN, have been obtained as a function of the stress-intensity factor range, ΔK, for Type 2219-T851 aluminum in ambient air at load ratios, R, of 0.1 and −1. Microscopic modes of crack extension were also determined by transmission electron fractography. Fatigue striation spacings, S, compared well with da/dN when static fracture modes—primarily dimpled rupture—did not occur. These static fracture modes were more prevalent during tension-tension loading at R = 0.1 than during tension-compression loading at R = −1, and they contributed to higher growth rates at the positive load ratio. The relationship between striation spacing and ΔK/E (where E is the elastic modulus) in Type 2219-T851 aluminum was found to be similar to those for other engineering alloys. This relationship was observed to be much less sensitive to changes in the load ratio than the relationship between da/dN and ΔK.

    Keywords:

    fatigue, cracks, growth, fractography, striation, failures, analysis of structure, ratios, aluminum 2219, materials, materials science


    Paper ID: STP33431S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP33431S


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