Dislocation structure developed in the austenitic-phase of SAF 2507 duplex stainless steel

Dislocation structures developed in the austenitic-phase of SAF 2507 duplex stainless steel during fatigue at total strain ranges of 0.8% and 1.2% have been investigated. According to this research, at total strain ranges higher than 0.8%, persistent slip bands (PSBs) can be formed within twins in the austenitic grains. Depending on the size of the twins, the ladder-like structure associated with PSBs can occupy the entire twin or part of them. Besides, a zone affected by the constraint of PSB at grain boundary could also be disclosed. Observations of the fracture surface for the highest total strain range have revealed the presence of intergranular secondary cracks, which were correlated with the PSB structure developed in narrow twins in the bulk of the material.