Dynamic strain aging under tensile and LCF loading conditions, and their comparison in cold worked 316L stainless steel

Abstract

Tensile and low-cycle fatigue (LCF) tests were carried out in a wide temperature range from 20 to 750 °C at strain rates of 1 × 10 −4–1 × 10 −2/s for 17% cold worked 316L stainless steel to investigate the conditions for the occurrence of dynamic strain aging (DSA) and its effects on material properties during tensile and LCF deformations. DSA introduced anomalous changes of tensile and LCF properties, and the DSA regimes under tensile and LCF loading conditions coincided with each other. During tensile deformation, DSA can be manifested in the forms of the plateau in the variation of strength with temperature, the minima in the variation of ductility with temperature, the serrated yielding in the stress–strain curves, and the negative strain rate sensitivity (SRS). As for LCF deformation, it can be manifested in the forms of the plateau or the peak in the variation of cyclic peak stress with temperature, the negative temperature dependence of plastic strain amplitude or softening ratio, the negative SRS, and the negative strain rate dependence of plastic strain amplitude or softening ratio.