STP733

    Fracture of Tungsten Wire in Metal Matrix Composites

    Published: Jan 1981


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    Abstract

    Mechanical properties were measured for the tungsten-fiber-reinforced Type 6061 aluminum and Type 1010 steel matrix composite systems. The tensile strength of the latter system was appreciably lower than the theoretical rule-of-mixture value. Auger spectroscopy and electron microprobe analysis showed significant iron contamination in the tungsten fibers. In addition, the tensile fracture mode at room temperature was shown to change from ductile to completely brittle upon annealing at 800 to 950°C, that is, just slightly above the fabrication temperature. Quantitative microanalysis showed that penetration of the iron diffusion front into the tungsten fiber coincided exactly with an annular fracture feature observed by scanning electron microscopy of tensile fracture surfaces. The strength degradation in steel/tungsten composites was due to fiber embrittlement caused partly by microstructural polygonization during the recovery process, but primarily by grain boundary diffusion of elemental iron from the steel matrix.

    Keywords:

    aluminum, annealing, diffusion, fractography, materials, materials science, metal matrix composite, steel, tensile strength, tungsten fiber


    Author Information:

    Kim, C
    Materials engineer, physical scientist, and supervisory materials engineer, Naval Research Laboratory, Washington, D.C.,

    Phillips, WL
    Materials engineer, physical scientist, and supervisory materials engineer, Naval Research Laboratory, Washington, D.C.,

    Weimer, RJ
    Materials engineer, physical scientist, and supervisory materials engineer, Naval Research Laboratory, Washington, D.C.,


    Paper ID: STP33438S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP33438S


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