STP1169: Internal Friction Investigation in High-Purity Tantalum and Niobium by Isothermal and Isochronal Measurements

    D'Anna, G
    Institut de Génie Atomique, Ecole Polytechnique Fédérale de Lausanne, Lausanne,

    Benoit, W
    Institut de Génie Atomique, Ecole Polytechnique Fédérale de Lausanne, Lausanne,

    Pages: 13    Published: Jan 1992


    Abstract

    A new apparatus for acoustic spectroscopy measurement has been built in order to observe the frequency response in tantalum and niobium. It permits the measurement of internal friction, elastic modulus change, and zero-point during a frequency sweep (isothermal damping spectra between 5 and 500 K) or temperature sweep (isochronal damping spectra between 10-4 and 10 Hz). It was possible to identify three interesting phenomena by the capability, offered by this new installation, of working isothermally in a low temperature range: (1) annealing of the gamma peak during a frequency sweep; (2) a strong temperature dependence of the Snoek-Köster peak's activation energy; and (3) activation of the {112} slipplane in an intermediate temperature range for screw dislocations.

    Keywords:

    material damping, internal stress, mechanical properties, internal friction, isothermal internal friction, tantalum, niobium, kink pairs formation, gamma peak, gamma peak annealing, hydrogen cold work peak


    Paper ID: STP17971S

    Committee/Subcommittee: E28.10

    DOI: 10.1520/STP17971S


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