STP427

    Metallurgical and Geometrical Factors Affecting Elevated Temperature Tensile Properties of Discontinuous Tungsten Fiber Reinforced Composites

    Published: Jan 1967


      Format Pages Price  
    PDF Version (668K) 27 $25   ADD TO CART
    Complete Source PDF (5.1M) 27 $57   ADD TO CART


    Abstract

    The length to diameter ratio and orientation of the fibers in discontinuous fiber reinforced composites was correlated to their elevated temperature tensile properties. Composites were made of copper and copper - 2 per cent chromium alloy reinforced with tungsten fibers having various length to diameter ratios. The composites were tested in tension at 300, 900, and 1500 F. These results were then compared with continuous length fiber reinforced composites containing the same matrix materials and fiber contents. The fiber orientation in the composite was found to be extremely critical at elevated temperatures. Shear failures occurred for specimens tested at 1500 F in which the fibers were misaligned from the tensile axis by as small as 3 deg. Composites which failed in shear had significantly lower tensile strengths than did composites having fibers aligned parallel to the tensile axis of the specimen. Tensile strengths of discontinuous fiber reinforced composites in which the fibers were aligned parallel to the tensile axis were dependent upon the length to diameter ratio of the fibers in the composite. As the length to diameter ratio of the reinforcing fibers decreased, the tensile strengths of the composites decreased. Alloying the copper matrix with chromium increased the matrix shear strength which was beneficial even though the alloying element reacted with the fiber. Load transfer from the matrix to the fiber was dependent upon the shear strength of the matrix. The greater the shear strength, the higher the load transfer capabilities of the matrix. The tensile strength of copper - 2 per cent chromium matrix composites thus was higher than unalloyed copper matrix composites having the same fiber content and the same length to diameter ratio fibers.

    Keywords:

    fiber metallurgy, filaments, composite metallurgy, tungsten, copper alloys, high temperature, tension tests


    Author Information:

    Petrasek, D. W.
    Lewis Research Center, Cleveland, Ohio.

    Signorelli, R. A.
    Lewis Research Center, Cleveland, Ohio.

    Weeton, J. W.
    Lewis Research Center, Cleveland, Ohio.


    Paper ID: STP42047S

    Committee/Subcommittee: D30.07

    DOI: 10.1520/STP42047S


    CrossRef ASTM International is a member of CrossRef.