Deformation mechanisms of a modified 316L austenitic steel subjected to high pressure torsion

The present work is assigned to the microstructural evolution of a modified 316L stainless steel during high pressure torsion (HPT) in a temperature range between -196 degrees C and 720 degrees C. The aspect of microstructural evolution is similar to that of materials with low stacking fault energy: at high deformation temperatures (T-def>450 degrees C) the dominant deformation mechanism is dislocation glide whereas for medium temperatures (450 degrees C>T-def>20 degrees C) mechanical twinning is observed. At very low deformation temperatures (20 degrees C>T-def>-196 degrees C) mechanical twinning is replaced by the deformation induced martensite transformation gamma(fcc) -> epsilon(hcp). Based on the present results, the formation mechanisms of nanocrystalline austenite are discussed. (C) 2010 Elsevier B.V. All rights reserved.