STP1169

    Nonlinear Internal Friction in a Premartensitic Cu74Al22Ni4 Alloy

    Published: Jan 1992


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    Abstract

    The dynamics of the stress-induced martensitic transformation in a Cu-15Al-3Ni alloy has been studied with finite amplitude internal friction. The resonance curves of a reed were measured in vacuum at resonance frequencies of 9, 22, 40, and 60 Hz and at temperatures of 93, 53, 23, -2, and -12°C. The frequency response equation resulting from the theory of the nonlinear anelasticity extended to the fourth order was used to analyze the resonance curves quantitatively. The linear damping showed a pronounced peak at 9 Hz and a small peak at 22 Hz at -2°C. The fourth order nonlinear damping displayed a large increase and the fourth order nonlinear elastic constant showed a steep decrease as the temperature approached the transformation temperature for all the resonance frequencies investigated. The anomalous temperature dependence of the linear damping and that of the ratio of the fourth order nonlinear damping to the fourth order nonlinear elastic constant at 9 Hz is interpreted in terms of the dynamics of a system governed by a double-well potential.

    Keywords:

    nonlinear anelasticity, nonlinear damping, martensitic transformation, internal friction, copper-aluminum-nickel alloy, material damping, internal stress, mechanical properties


    Author Information:

    Hwang, I-C
    Research associate and acting chairman, University of Maryland, College Park, MD

    Wuttig, M
    Research associate and acting chairman, University of Maryland, College Park, MD


    Paper ID: STP17972S

    Committee/Subcommittee: E28.10

    DOI: 10.1520/STP17972S


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