Asymmetric creep modeling of common refractory ceramics with high temperature wedge splitting test

Abstract

Common refractory ceramics display significant asymmetric creep behavior at high temperatures under uniaxial loading conditions. This study introduces an advanced asymmetric creep model based on the stress path in the hydrostatic pressure–von Mises stress diagram. The developed creep model was applied in the modeling of high-temperature wedge splitting test procedure, where tensile and compressive stresses simultaneously occur perpendicular to the loading direction during testing at high temperatures. A case study of magnesia chromite material at different temperatures was performed to assess the creep contribution to the nominal total fracture energy at different temperatures and determine the pure mode I fracture parameters. Under the present testing conditions, the creep contribution is 13% at 1300 °C and 1400 °C and 5% at 1500 °C for the magnesia chromite material. The ratio of the nominal notch tensile strength to the pure tensile strength is 1.54–2.11, which decreases monotonically with respect to the brittleness number. The necessity to determine creep functions in multiaxial compression, multiaxial tension or tension–compression loading area shall be identified case by case.