Thermal aging effect on the ratcheting-fatigue behavior of Z2CND18.12N stainless steel

• The effects of thermal aging periods and temperature on fatigue are significant.
• The ratcheting strain increases with increasing thermal aging time and temperature.
• We introduce an aging damage factor to predict the ratcheting-fatigue life.

The uniaxial tensile and ratcheting-fatigue behaviors of the Z2CND18.12N austenitic stainless steel at room temperature were studied with different thermal aging periods (from 1 h to 500 h) at different thermal aging temperatures (500 °C and 700 °C). The thermal aging process resulted in apparent changes in the ratcheting behavior and the ratcheting-fatigue life. The precipitates under different thermal aging conditions were identified by SEM observation. Considering the deterioration of the material induced by thermal aging process, aging damage factor was introduced to predict the ratcheting-fatigue life, which resulted in good prediction for all the thermal aging conditions.