Tensile creep of miniaturized specimens

LiKang Luan, Heinz Riesch-Oppermann, Martin Heilmaier
A customized-built high-temperature tensile creep setup is introduced. Dog-bone shaped miniaturized specimens made from Nimonic-75 were tested as reference materials at temperatures of 850 and 1000°C under constant load to verify the setup's accuracy. The results were compared to tensile creep tests with conventional (standard size) specimens at identical experimental conditions. The shape of the creep curves obtained in the miniaturized specimens exhibits a pronounced minimum creep rate, thus,
more » ... m creep rate, thus, being seemingly different from the ones obtained for the bulk samples which reveal a clear steady-state regime. This is partly due to the continuous increase of stress under constant load testing conditions and very likely affected by the much higher surface to volume ratio of the miniaturized specimens leading to the premature onset of tertiary creep. Still, a good agreement was obtained between the two specimen sizes with respect to the dependence of the steady-state (standard size) and minimum (miniaturized size) strain rate on applied stress at various temperatures leading to also comparable activation energies of the creep.
doi:10.5445/ir/1000078479 fatcat:qqqub5pscnan7birvz3ibuwjki