STP1201

    Creep Behavior of Silicon Nitride Determined From Curvature and Neutral Axis Shift Measurements in Flexure Tests

    Published: Jan 1994


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    Abstract

    The creep behavior of a hot-pressed silicon nitride was determined in flexure in air at 1200 and 1300°C by monitoring the creep deflection, the specimen curvature and the position of the neutral axis. The resulting data was used to evaluate the steady-state creep rate from the conventional elastic solution, curvature-moment relations and a model accounting for neutral axis shift. Fractography and measurements of specimen compliance before and after testing indicated bulk cracking and a loss of stiffness. The validity of flexural data to determine creep life parameters was considered.

    Keywords:

    silicon nitride, creep, tension, compression, bending, flexure, neutral axis, cracking, stiffness


    Author Information:

    Salem, JA
    Materials Research Engineer, NASA LeRC, Cleveland, OH

    Choi, SR
    Resident Research Associate, Cleveland State University, Cleveland, OH


    Paper ID: STP12776S

    Committee/Subcommittee: C28.01

    DOI: 10.1520/STP12776S


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