On the assessment of tensile work hardening behaviour of type 316L(N) austenitic stainless steel in the framework of θσd vs. σd using flow stress contribution from dislocations

The experimental θσd vs. σd data (where θ = dσd/dεp is the instantaneous work hardening rate, σd is flow stress contribution from dislocations and εp is the plastic strain), which are equivalent to dρ/dεp vs. ρ1/2 (ρ is the dislocation density), provide better insight into the different stages of work hardening behaviour of 316L(N) stainless steel in three temperature regimes. The steel exhibited three-stage work hardening behaviour characterised by a gradual increase in θσd at low stresses (transient stage) followed by a linear increase in θσd in stage-II and inverted parabolic hardening at high σd in stage-III. The critical parameters assessed from the θσd vs. σd plots exhibited anomalous variations due to dynamic strain ageing occurring at intermediate temperatures. At high temperatures, the variations in parameters with temperature and strain rate exhibited dominance of dynamic recovery. Irrespective of temperature and strain rate conditions, the observed higher fraction of stage-III work hardening over other fractions indicates that the concurrent evolution of storage and annihilation of dislocations dominates over storage of dislocations during deformation.