Effect of oxidation on creep data: Part 2-A procedure for assessing the effect of oxidation on constant-stress or constant-load creep curves using the Theta-projection concept

A procedure based on Theta-methodology coupled with the knowledge of oxidation kinetics is envisaged for quantitatively assessing the effect of oxidation on creep curves. The procedure is based on the generation of a series of real constant-stress creep curves, at different stress and temperature levels. in inert atmosphere, where the effects due to oxidation are kept to a minimum level. Stress enhancement factors due to the effect of area reduction on specimen cross-section with plastic deformation and oxidation are defined for constant-stress or constant-load creep testing. These factors can be used in the integration of the strain-rate equation related to the 40 - parameter analysis, to derive constant-stress or constant-load curves in air using either the strain hardening or time hardening theories. Although systematic constant-stress creep data in vacuum are not yet available to test the methodology effectively, a preliminary simulation is done to demonstrate how the model works. to check its performance and the possibilities of analysis.