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 ∼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.