STP1304

    Comparison of Elastic and Anelastic Properties of SiC and MoSi2/Ti5Si3 as a Function of Temperature

    Published: Jan 1997


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    Abstract

    The piezoelectric ultrasonic composite oscillator technique (PUCOT) was used at frequencies near 120 kHz to measure the elastic and anelastic properties of two kinds of advanced ceramics as a function of temperature (T) up to about 1300 K and of strain amplitude in the range 10-7 to 10-4. The specimens consisted of commercially available silicon carbide (SiC) from Norton Co., reaction-formed SiC (RFSC) [with and without molybdenum disilicide (MoSi2) additions] made at NASA Lewis Research Center, and MoSi2/Ti5Si3 [With Ti5Si3 (pentatitanium trisilicide) concentrations in the range 10 to 50%] made at Los Alamos National Laboratory. The measured values of dynamic Young's modulus, E, damping, Q-1 and strain amplitude were analyzed. The main findings are: The Values of (1/E(0))(dE/dT), where E(0) is the value of E at room temperature, fall near -3 X 10-4 K-1; the damping in the materials is small and independent of strain amplitude for most of the specimens and temperatures used; and limited data for the silicides with 30 and 40% Ti5Si3 indicate a breakaway of the strain amplitude dependence of damping. The similarities and differences in the behavior of the mechanical properties are discussed for the two types of material.

    Keywords:

    ceramics, silicon carbide, molybdenum disilicide, pentatitanium trisilicide, elastic, anelastic, temperature, ultrasonics, Young's modulus, damping, strain amplitude


    Author Information:

    Wolfenden, A
    Professor, and undergraduate research assistants, Texas A&M University, College Station, TX

    Bauer, KJ
    Professor, and undergraduate research assistants, Texas A&M University, College Station, TX

    Kury, PB
    Professor, and undergraduate research assistants, Texas A&M University, College Station, TX

    Oliver, KA
    Professor, and undergraduate research assistants, Texas A&M University, College Station, TX

    Rynn, PJ
    Professor, and undergraduate research assistants, Texas A&M University, College Station, TX

    Petrovic, JJ
    Materials scientist, Los Alamos National Laboratory, Los Alamos, NM

    Singh, M
    Senior research engineer, NYMA, Inc., Lewis Research Center Group, Cleveland, OH


    Paper ID: STP11750S

    Committee/Subcommittee: E28.02

    DOI: 10.1520/STP11750S


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