Serrated flow accompanied with dynamic type transition of the Portevin–Le Chatelier effect in austenitic stainless steel

Abstract

• By introducing high-temperature DIC analysis, the PLC effect in an Fe-19Cr-13Ni-0.2C austenitic stainless steel was investigated. • Various types of serrated flow associated with the diffusion of interstitial C atoms appeared at temperatures from 473 K to 623 K, and the type dynamically changed even at an applied strain rate. • High-temperature DIC analysis revealed the dynamic type transition of serrated flow obeyed the variation in PLC band nucleation and propagation behavior. • Numerical modeling proves that the spatial-temporal coupling effect plays an important role in the microscopic nucleation manner of the PLC band. In order to further understand high-temperature deformation behavior and its-related mechanical properties, the Portevin–Le Chatelier (PLC) effect in an Fe–19Cr–13Ni–0.2C austenitic stainless steel was investigated using high-temperature digital image correlation (DIC) analysis. Under the tensile testing at temperatures from 473 K to 623 K, different types of serrated flow appeared even at a constant applied strain rate, and the type transition took place dynamically in a certain order with deformation time. DIC analysis revealed that the dynamic type transition of the serrated flow obeys the PLC band propagation behavior, and that the transition of the PLC band propagation behavior could be attributed to the PLC band nucleation manner. Numerical modeling also proved that the nucleation manner of PLC band nucleation is determined by the spatial-temporal coupling effect.