Volume 21, Issue 5 (September 1993)
A Mechanical Extensometer for High-Temperature Tensile Testing of Ceramics
Design and development of a simple mechanical strain extensometer for high-temperature tensile testing of ceramic materials are described. The extensometer uses the lever-arm concept to proportionally reproduce the displacements of fiducial gage marks defined on a specimen. Various potential errors in strain measurement associated with the kinematics of this mechanical extensometer are analyzed and estimated. The extensometer exhibits a resolution of 5 microstrain (μɛ) and good long-term stability under moderate changes of ambient temperature. Limited results of simple isothermal creep tests on silicon nitride tensile specimens are presented to demonstrate the effectiveness of the device.