True stress-true strain relations with very low strain rates at room temperature for an austenitic 25Cr-19Ni steel

摘要

True stress (σ)-true strain (ε) relations at very low strain rates at room temperature are compared in creep and tensile tests to investigate the effect of deformation history on the σ-ε relation and the applicability of the Kocks-Mecking (KM) model for the austenitic 25Cr-19Ni steel. Experimental results obtained by the creep and the tensile tests indicate that the σ-ε relation is not influenced by prior deformation history at true strains below 0.2. The σ-ε curves at very low strain rates between 10^-8 and 10^-10 s^-1 obtained by the creep test are in accordance with those calculated by the KM model as well as that measured by the crosshead-arresting test. The KM model is concluded to be applicable to the σ-ε relations at very low strain rates obtained by various deformations.