A study of the mechanical and fatigue properties of metallic microwires

Golta Khatibi, Agnieszka Betzwar-Kotas, Viktor Gröger, Brigitte Weiss

    Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

    Abstract

    There is an increasing necessity to record the deformation characteristics of microelements containing freestanding bond wires. The data required are either mechanical or thermal such as Young's moduli, stress-strain values, fatigue-and thermal-strain data, but the nominal strength of a structure changes by scaling its size. Due to this size effect, material data cannot be taken from macrospecimens, thus special testing procedures were introduced. Laser optical sensors based on the speckle correlation technique were applied to determine non-contacting strain values with high strain resolution. For the mechanical properties tensile tests were used. A special ultrasonic resonance fatigue system is described for testing freestanding microwires. In this study the str ess-strain and fatigue response of microwires of Cu with a purity of 99.99+% with diameters between 10 and 125 ?m with a typical bamboo structure have been investigated. A size dependence of the yield strength which increased with decreasing diameter was observed, while the fracture elongation showed contrary behaviour. Fatigue life also decreased with reduced diameters. An explanation is p resented based on formed oxide layers, strengthening effects by dislocation pile-ups and a pronounced localization of formed slip steps acting as notches being most dominant in the very thin microwires. Œ 2005 Blackwell Publishing Ltd.
    OriginalspracheEnglisch
    Seiten (von - bis)723-733
    Seitenumfang11
    FachzeitschriftFatigue & Fracture of Engineering Materials and Structures
    Jahrgang28
    Ausgabenummer8
    DOIs
    PublikationsstatusVeröffentlicht - 2005

    ÖFOS 2012

    • 1030 Physik, Astronomie

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