Excellent ductility of an austenitic stainless steel at a high strength level achieved by a simple process.

[Display omitted] • A new austenitic stainless steel with high strength and excellent ductility was designed and manufactured by simple method. • The elongation of samples is up to 53.5–61 % under the yield and ultimate tensile strength level of 600–707 and 977–1020 MPa. • The product of strength and plasticity of this steel is the highest value comparing with other austenitic stainless steels. • There is the highest yield strength in this steel comparing with other austenitic stainless steels at the same elongation. • The excellent mechanical property of this steel is ascribed to a new multi-element collaborative strengthening mechanism. In the pursuit of simultaneously improving the yield strength and plasticity of austenitic stainless steel, a new austenitic stainless steel was fabricated by induction smelting using a pure N 2 atmosphere, hot forging, cryogenic rolling, and annealing. The material was characterized by microstructures with 3–4 μm uniform finer grains, fine precipitates, high thermal stability austenite, and extensive high-angle grain boundaries. The elongation after fracture, yield strength, and ultimate tensile strength of the samples reached 53.5 %, 707 MPa, and 1020 MPa, respectively, as well as 61 %, 600 MPa, and 977 MPa, respectively, at the same time. Moreover, a high strain hardening rate was achieved in the new stainless steel. The appropriate uniform finer grains not only played a role in grain-refined strengthening but also provided intragranular spaces and sufficient mean free available paths for dislocation accumulation and movement. Precipitates, which were coherent or semi-coherent with the matrix, provided interfaces for dislocation accumulation and obstructions for dislocation movement. Extensive high-angle grain boundaries with appropriate finer grains served as another important factor for excellent ductility due to the inhabitation and resulting deviation of crack propagation. In addition, strain-induced mechanical twinning in the current austenitic stainless steel contributed to excellent ductility and high strength. [ABSTRACT FROM AUTHOR]