Tensile ductility of nanotwinned austenitic grains in an austenitic steel

Dynamic plastic deformation followed by recovery annealing of an austenitic stainless steel results in the formation of a hierarchical microstructure consisting of nanotwinned austenitic grains (>55 vol.%) mixed with nanograins and dislocation structures. The sample exhibits a yield strength of 1055 MPa and a uniform elongation of similar to 5.2% with a considerable work hardening. Such a remarkable tensile ductility originates from the intrinsic plasticity of the nanotwinned austenitic grains in which dislocation density is reduced after the recovery annealing. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.