Tomographic method for evaluation of apparent activation energy of steady-state creep

A new method for the evaluation of the apparent activation energy of steady-state creep in metals is presented. It is based on in situ monitoring by microtomography the geometry of a specimen subjected to uniaxial load and inhomogeneous temperature distribution. It is shown that microtomography acting as a three dimensional extensometer enables the evaluation of local strain-rates of small material volumes and is an adequate tool for characterization of inhomogeneously deforming specimens. Activation energies obtained with the new method for stainless steel agree within an error of 5% with values obtained according to the classical procedure.