Strain Partitioning and Softening Mechanisms of δ/γ in Lean Duplex Stainless Steels during Hot Deformation

Abstract

A novel lean duplex stainless steel (DSS) with excellent hot workability is successfully developed, referred as 21Cr‐DSS. The strain partitioning and softening mechanisms of the constituent phases in the novel steel are elucidated and compared with the conventional DSS. The strain is preferentially accommodated in the soft ferrite phase, leading to the significant strain localization and a faster restoration of dynamic recovery and dynamic recrystallization (DRV or DRX) in ferrite, whereas conventional DSS is characterized by inhomogeneity in softening and incompatibility in deformation between ferrite and austenite, which promotes the propagation of cracks along the δ/γ interface during hot deformation. However, the novel 21Cr‐DSS exhibits homogeneous strain–stress partitioning in δ/γ, especially at low deformation temperature, resulting in superior deformation compatibility between ferrite and austenite.