Deformation Mechanism of Bimodal Structured 2205 Duplex Stainless Steel in Two Yield Stages.

A kind of micro/nanostructured 2205 duplex stainless steel (DSS) with uniform distribution of nanocrystals was prepared via aluminothermic reaction method. The analysis of stress-strain curve showed that the fracture strength and elongation of the specimen were 946 MPa and 24.7%, respectively. At present, the research on microstructure of bimodal 2205 DSS at room temperature (RT) mainly depended on scanning electron microscope (SEM) observation after loading experiments. The test result indicates that there are two different yield stages in stress-strain curve of specimen during tensile process. The microstructure of duplex bimodal structured stainless steel consists of two pairs of soft hard regions and phases. By studying deformation mechanism of bimodal structured stainless steel, the interaction between soft phase and hard phase are discussed. The principle of composition design and microstructure control of typical duplex stainless steel is obtained, which provides an important research basis for designing of advanced duplex stainless steel. [ABSTRACT FROM AUTHOR]