A comparative assessment of cyclic deformation behavior of SA333 Gr-6 steel at ambient and elevated temperatures

The aim of this investigation is to study the comparative cyclic deformation behavior of SA333 Gr-6 steel at two different temperatures. Strain-controlled low cycle fatigue experiments were carried out at 1 × 10–3 s–1 strain rate at room temperature and 300 °C. Cyclic hardening of the steel was observed at both the temperatures. However, greater cyclic hardening was observed at 300 °C for all the strain amplitudes. Non-Masing behavior was observed at both the temperatures. Greater deviation from Masing behavior was observed at 300 °C due to generation of more dislocation activities. Higher dislocation density and sub-cell structure formation is associated with the hardening characteristic of the material. Lower fatigue lives were observed for all strain amplitudes at 300 °C in comparison to room temperature. This is due to the deleterious effect of dynamic strain aging, which is activated at 300 °C. The fracture surface reveals that with an increase in strain amplitude the number of crack initiation sites increases and the region decreases, which leads to a reduction in fatigue life.