Microstructures and Corrosion Behaviors of an Austenitic Stainless Steel Strengthened by Nanotwinned Austenitic Grains

A novel type of nanotwinned austenitic stainless steel consisting of the nanotwinned grains embedded in coarsened nano-sized grains and recrystallized matrix was synthesized. Potentiodynamic polarization measurements indicate that the nanotwinned samples exhibit a higher passive ability in the acidic solution and a comparable pitting resistance in chloride solution in comparison with that of their coarse grained counterparts. The effects of the microstructure, specifically the presence of nanotwinned grains, on the corrosion resistance are discussed. The nanotwinned austenitic stainless steel possesses an excellent combination of strength and ductility as well as corrosion resistance.