Comparison of strength-ductility combinations between nanotwinned austenite and martensite-austenite stainless steels

Two types of austenitic stainless steel samples were prepared by means of dynamic plastic deformation followed by annealing: nanotwinned austenitic grains embedded in recrystallized austenite matrix and martensitic/austenitic duplex microstructures. Annealing at 923 K induced martensitic reversion while most nanotwinned grains are stable. An enhanced strength-ductility combination is observed in the annealed nanotwinned samples which exhibit a uniform elongation of ~21% and a yield strength of ~900 MPa, in contrast to a uniform elongation of ~12% with comparable strength in the martensitic/austenitic samples.