Ferrite-austenite synergistic deformation behavior in a 2205 duplex stainless steel containing equiaxed austenite domains

This study investigates the mechanical properties and deformation behavior of 2205 duplex stainless steel (DSS) through a two-stage solution (TSS) process. The TSS process involves heat treatment at 1380 degrees C for 20 min, followed by 1000-1200 degrees C for 20 min. This process achieves a favorable balance between strength and plasticity, resulting in a yield strength ranging from 585 to 607 MPa, an ultimate tensile strength ranging from 796 to 802 MPa, and a fracture elongation ranging from 28.4% to 32.8%. The activation and transmission of slip systems within the constituent phases, as well as the interaction between dislocations and different interfaces, are examined via in-situ electron backscatter diffraction, in-situ scanning electron microscopy, and transmission electron microscopy. The results indicate that slip transfer is the primary mechanism by which austenite and ferrite adapt to coordinated deformation in DSS 2205. Furthermore, the possibility of dislocation slip across boundaries is assessed using the Luster-Morris parameter (m'). When m' exceeds 0.81, activated dislocations within the austenite grains can traverse the Kurdjumov-Sachs (K-S) and Nishiyama-Wassermann (N-W) interfaces, promoting coordinated dislocation slip in the ferrite matrix. Dislocation motion remains uninhibited at the ferrite-austenite interface, while accumulation at the ferrite grain boundaries leads to localized stress concentration.