STP520

    Effect of Interrupting Fatigue by Periods of Heat for Aluminum Alloy Structural Elements

    Published: Jan 1973


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    Abstract

    Effects of heat on fatigue have been studied by interrupting fatigue tests at ambient temperature by single periods of heating with and without steady load applied. The tests employed constant amplitude and random loading on various structural elements in a number of aluminium-copper alloy materials. Heating was applied at temperatures in the range 100 to 150 C for times ranging from 1 h to 20 000 h.

    The initiation of fatigue cracks was affected by heating, particularly at temperatures above 110 C when the effects occurred comparatively rapidly. The two mechanisms of importance were changes in microstructure at the machined surface which encouraged initiation, and changes in residual stress by creep which encouraged or discouraged initiation according to the creep being compressive or tensile.

    It is suggested that similar mechanisms operate also during the crack propagation phase of the fatigue life.

    Keywords:

    fatigue (materials), cracking (fracturing), structural members, aluminium copper alloys, work hardening, heat treatment, creep properties, residual stress, supersonic transports


    Author Information:

    Heath-Smith, JR
    Principal scientific officer and scientific officer, Royal Aircraft Establishment, Farnborough, Hants

    Kiddle, FE
    Principal scientific officer and scientific officer, Royal Aircraft Establishment, Farnborough, Hants


    Paper ID: STP38866S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP38866S


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