Superior Strength and Ultrahigh Ductility in Hierarchical Structured 2205 Duplex Stainless Steel from Nanoscale to Microscale

A laminated structured 2205 duplex stainless steel (DSS) with graded grain size was prepared via aluminothermic reaction and subsequent hot rolling deformation of 80% at 1000°C, its mechanical properties, strengthening toughening mechanism were studied. Our materials have extraordinary elongation 54% high tensile strength 990 MPa. The lamellar structure is characterized heterogeneous lamella austenite (with nano-grain, ultrafine grain, micro-grain nano-twin) ferrite a proper amount micro grain) coalesced alternately. attributed to complex (distribution from nanoscale microscale) interfaces arising hierarchical dual-phase distribution. unusual ductility thought be mainly the dislocation hardening.