Dynamic strain aging effects on low-cycle fatigue of AISI 430F

The effects of dynamic strain aging (DSA) on the cyclic mechanical behavior were investigated in a ferritic steel type AISI 430F. Strain-rate changes performed during cyclic tests show a negative strain-rate dependence of the flow stress for temperatures ranging from 200 °C to 450 °C. Low-cycle fatigue curves exhibit prominent cyclic hardening at 400 °C and 450 °C. The influence of the embrittlement phenomena on the hardening of this ferritic steel was also investigated by performing aging treatments at 400 °C and 450 °C in the alloy. These results suggest that a DSA mechanism is operative in this material in a temperature range between 300 °C and 400 °C. Stress relaxation experimental results are also discussed in terms of dynamic strain aging.