Effect of hydrogen charging on the microstructure evolution of duplex stainless steel

The influence of hydrogen on the microstructure of austenitic–ferritic duplex stainless steel (DSS) was investigated. The thin foils after cathodic hydrogen charging were examined using transmission electron microscopy (TEM). The effect of various experimental conditions (i.e., current density, type of the electrolyte and presence of the hydrogen recombination poison) on the microstructure evolution during cathodic hydrogen charging was studied. The characteristic changes of the α and γ phases were observed. The microstructural changes in the γ phase consist in an increase of stacking faults and dislocations density. The possible explanations of the effects observed were discussed. It was concluded that the appropriate choice of the experimental conditions permits us to control the microstructure evolution rate resulting from the hydrogenation process.