Recent advances in dissolution kinetics of sigma phase in duplex stainless steels

Sigma phase is well known as a detrimental phase that causes considerable reduction in plasticity and corrosion resistance of duplex stainless steels (DSS). From a practical viewpoint, the occurrence of this phase as early as in the production process with associated brittleness, constitutes a problem of paramount importance. For this reason, the precipitation kinetics of sigma phase was extensively studied in literature. On the contrary, less attention has been paid to investigate the microstructure evolution of DSS during heating, which is of primary importance when a thermal treatment must be planned. As a matter of fact, any undissolved precipitates or chemical non-uniformity in the parent phase greatly affect both the material properties at room temperature and the subsequent precipitation process during cooling. Starting from a kinetic dissolution model recently published in literature, recent advances in dissolution kinetics of sigma phase in duplex stainless steels are presented in this work.