Influence of thermal cycling on the microstructure of a ferritic-austenitic duplex stainless steel

The influence of thermal cycling without any applied load on the microstructural features of a forged stainless ferritic-austenitic duplex steel was investigated by transmission electron microscopy. The steel was examined in uncycled and cycled conditions. Thermal cycling between 20 °C and 900 °C did not alter the volume fractions and the anisotropic grain structure of ferrite and austenite. On the other hand, thermal cycling had a strong influence on the dislocation arrangement in both phases. Three different types of precipitate were identified in the uncycled material. The amount of these particles was increased by thermal cycling. There was a strong evidence for the precipitation of α′ particles in the cycled material.