Micro/nano-structure leads to super strength and excellent plasticity in nanostructured 304 stainless steel

Abstract

Micro/nano-structure is one of the important types of multilayer construction, which can make nanocrystalline metals and alloys with excellent comprehensive mechanical properties. By means of Aluminothermic Reaction (AR) and subsequent rolling with deformation of 50% at room temperature (RT) and followed by annealed at 973 K for 1 h, a heterogeneous composite structure of micro/nano-structured 304 stainless steel (SS) is obtained. Such a stainless steel specimen exhibits a tensile strength as high as 1023 MPa and an elongation-to-failure of about 27.3%. In the process, the much elevated strength originates from martensite strengthening, austenite grain refinement and dislocation density increasing, while ductility promotes from the recrystallization of deformed austenite and recovery of strain induced martensite. Superior strength–ductility combination achieves in micro/nano-structured 304 SS, which demonstrates a novel approach for optimizing the mechanical properties in engineering materials.