A novel approach to achieve high yield strength high nitrogen stainless steel with superior ductility and corrosion resistance

A complex structure consisting of ultrafine-grained processed zone and coarse-grained base material zone was developed in this study, aiming at improving the yield strength of a high nitrogen stainless steel without sacrificing corrosion resistance and ductility. The ultrafine-grained processed zone was produced by friction stir processing, leading to ultra-high strength and great pitting corrosion resistance, but significantly reduced ductility; the coarse-grained zone exhibited excellent ductility but a very low yield strength. The enhancement and coordination between the processed zone and coarse-grained zone resulted in significantly improved yield strength and ductility of the complex structure. Thus, a combination of excellent mechanical properties and corrosion resistance was successfully achieved. (C) 2019 Elsevier B.V. All rights reserved.