| Abstract | Cast austenitic stainless steel 1.4848 is used to manufacture automotive exhaust system components. Low cycle fatigue (LCF) of 1.4848 austenitic steel was investigated through strain-controlled fatigue testing at strain rates of 0.02/s, 0.002/s, and 0.0002/s in the temperature range from room temperature (RT) to 900°C. Its cyclic behavior was characterized in relation to deformation mechanisms. At RT, the material behavior was rate-independent and cyclically stable, which occurred by plasticity. The material exhibited significant cyclic hardening at intermediate temperatures, 400°C to 600°C, with negative strain-rate sensitivity. In this temperature range, dynamic strain aging (DSA) presumably occurred due to slip dragging solute atoms. At high temperatures, 800°C and 900°C, the material exhibited positive rate-dependence in the hysteresis behavior, and the cyclic stress response tended to stabilize with increasing cycles. The high-temperature behavior was presumably controlled by a combination of plasticity and dislocation-glide creep. The integrated creep-fatigue theory (ICFT) was used to describe the deformation and life behaviors based on the identified mechanisms, which were corroborated by fractographic observations. Copyright © 2017 by ASTM International. |
|---|
