Effect of mean stress and stress amplitude on the ratcheting behaviour of 316LN stainless steel under dynamic strain aging regime

摘要

The influence of dynamic strain aging (DSA) on the ratcheting behaviour of 316LN stainless steel was investigated at 823 K as a function of mean stress (σ_m) and stress amplitude (σ_a). Test results obtained under different combinations of σ_m — σ_a were analysed in order to arrive at a map delineating different deformation regimes viz. ratcheting, strain burst and elastic shakedown. It was shown that the synergistic effect of σ_m and σ_a can be described by the ratio of mean stress and stress amplitude (σ_m/σ_a). A critical value of this ratio was identified to mark the transition between ratcheting and elastic shakedown and the same was used to predict deformation behaviour of the material in DSA under asymmetrical loading.