Peculiarities of DRX in a Highly-Alloyed Austenitic Stainless Steel

The features of discontinuous dynamic recrystallization (DRX) in a highly-alloyed austenitic stainless steel were studied at temperatures of 800 degrees C to 1100 degrees C. Hot deformation accompanied by DRX was characterized by an activation energy of 415 kJ/mol. The frequency of the sequential DRX cycles depended on the deformation conditions; and the largest fraction of DRX grains with small grain orientation spread below 1 degrees was observed at a temperature of around 1000 degrees C and a strain rate of about 10(-3) s(-1). The following power law relationships were obtained for DRX grain size (D-DRX) and dislocation density (rho) vs. temperature-compensated strain rate (Z) or peak flow stress (sigma(P)): D-DRX similar to Z(-0.25), rho similar to Z(0.1), sigma(P) similar to D-DRX(-0.9), sigma(P) similar to rho(1.4). The latter, i.e., sigma(P) similar to rho(1.4), was valid in the flow stress range below 300 MPa and changed to sigma(P) similar to rho(0.5) on increasing the stress. The obtained dependencies suggest a unique power law function between the dislocation density and the DRX grain size with an exponent of -0.5.

Automated summary

The features of discontinuous dynamic recrystallization in a highly-alloyed austenitic stainless steel were studied, showing power law relationships between DRX grain size and dislocation density with temperature-compensated strain rate or peak flow stress. The obtained dependencies suggest a unique power law function between the dislocation density and the DRX grain size.