Dynamic recovery and dynamic recrystallization competition on a Nb- and N-bearing austenitic stainless steel biomaterial: Influence of strain rate and temperature

The objective of this study was to investigate the dynamic softening behavior of an austenitic stainless steel with high nitrogen (type ISO 5832-9) through hot torsion tests, in the temperature range of 900–1200 °C and in the strain rate range of 0.01–10 s−1. The shape of flow stress curves indicated that the softening was promoted by dynamic recovery followed by dynamic recrystallization with high level of recovery. The microstructure evolution indicated that even though after large straining as that of the steady state stresses a combination of strained and recrystallized grains was observed. The delay of dynamic recrystallization, which is a consequence of the intermediate level of stacking fault energy of this steel, and the presence of large recrystallized grains, inside of necklace formed by small grains, were associated with extended recovery regions.