In-situ transmission electron microscopy investigation of the deformation behavior of spinodal nanostructured δ-ferrite in a duplex stainless steel

In-situ compression tests in a transmission electron microscope were carried out to investigate the deformation behavior of δ-ferrite nanopillars of a duplex stainless steel. The δ-ferrite with a spinodal nanostructure, which formed due to aging at 475°C for 64h, obviously suppressed the progress of serrated yielding (a series of short strain bursts) relative to that without the spinodal nanostructure. The results revealed that during compression deformation, the spinodal nanostructure confined the movement of dislocations (leading to a significant increase in dislocation density), causing a notable strengthening effect, and also kept the slip band morphology planar.