EBSD characterization of martensitic transformation and texture evolution in lean duplex stainless steel under uniaxial loading

In this work, EBSD technique was applied to investigate the martensitic transformation characteristics and texture evolution laws in a lean duplex stainless steel (present LDX) along several uniaxial loading paths (i.e., tension, compression, cyclic tension-compression at ε a =1.0% and pre-tension of 10%≤ ε pre ≤30% plus cyclic tension-compression at ε a =1.0%). The results showed that martensitic transformation occurs in austenite under all these loading conditions. Tensile loading is more favorable for martensitic transformation than compressive loading, and a higher tensile pre-strain is more favorable for martensitic transformation during the subsequent cyclic deformation. In BCC (ferrite plus α' bcc -martensite) phases, the initial Cubic texture disappears and rotated Cubic texture appears under uniaxial loading. Besides, a strong γ fiber texture <111>//Z and a weak rotated Goss texture are also present under compressive loading and cyclic loading, respectively. In austenite phase, the initial rotated Goss texture and D texture disappear and the initial Goss texture remains under tensile/compressive loading ( ε ≤0.262). Additionally, <111>//X fiber texture and <110>//Z fiber texture are shown under tensile and compressive loading, respectively. While under cyclic loading, austenite shows a gradual randomization of grain orientation inside. As for the pre-strained specimens, the major tensile textures in BCC and FCC phases, although show reduced intensities under cyclic loading, are largely preserved after cyclic failure.