Atomic force microscopy investigation of surface relief in individual phases of deformed duplex stainless steel

Atomic force microscopy was applied to study the surface relief evolution in the two phases of a duplex stainless steel subjected to different tensile plastic deformations. Due to their morphology, the slip markings can be easily distinguished between austenite and ferrite. Straight slip bands were observed in austenite. In ferrite, slip bands could be classified into two different groups depending they resulted from the bulk activities of ferrite or whether their formation was assisted by the plastic deformation of austenite. It was found that the crystallographic misorientation based on a Kurdjumov–Sachs relationship was the factor controlling one or the other type. The number of slip bands in both phases increased with the applied plastic strain but this effect can be masked by the coalescence of small smooth slip bands to large jagged slip bands for the austenite phase and by the evolution of the morphology in the ferrite phase.