Abstract:
Dynamic strain ageing (DSA) behavior of modified 9Cr-1Mo steel under uniaxial tensile and constant strain cyclic loading is
presented in this paper. Tensile tests are carried out at different strain rates from 10-3 to 10-5 s-1 in the temperature range from
room temperature to 600 °C. DSA has been established in the temperature range between 250 and 400°C in terms of peak in
tensile strength, minima in ductility, serrated plastic flow and negative strain rate sensitivity. In the region of DSA dislocation
substructure revealed high density of dislocations and features like kinks and bowing of dislocations are observed. Low cycle
fatigue behavior was studied at 300°C, over a wide range of strain amplitudes at different strain rates. An inverse effect of strain
rate was observed on cyclic stress response and fatigue life at 300 °C due to DSA.
