First observation by EBSD of martensitic transformations due to hydrogen presence during straining of duplex stainless steel

A comparative study of the active deformation mechanisms in duplex stainless steel is performed during straining with and without hydrogen charging. Interrupted tensile tests at an equal strain level clearly show that hydrogen influences how plastic deformation is accommodated. Slip planarity and martensite formation in austenite is observed for the hydrogen charged condition while dislocation multiplication and cross-slip take place for the uncharged condition. Three possibilities are put forward to explain the change: the reduction in stacking fault energy by hydrogen, a shift with respect to what phase accommodates most of the plastic strain and hydrogen pinning edge dislocations and thus restraining them to shift to the screw dislocation type and cross-slip.