Abstract
Austenitic-ferritic duplex stainless steel was cycled with three constant stress amplitudes and different mean stresses and cyclic stress-strain response and fatigue life were measured. Fatigue hardening/softening curves and cyclic creep curves were recorded. Saturated plastic strain amplitude was plotted vs. stress amplitude to obtain cyclic stress-strain curves for different mean stresses. The dependence of the cyclic stress-strain curve on the mean stress was established. Cyclic creep rate decreases progressively during the fatigue life leading to saturation of the mean stress. Fatigue life decreases with the mean stress and different representation of the fatigue life curves were presented and discussed in terms of crack initiation and growth.

Key words
cyclic plasticity, cyclic creep, mean stress, fatigue life, duplex steel

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