Hydrogen Dragging and Transportation by Moving Dislocation in 316L and 304 Stainless Steels

摘要

The interaction between dislocation and hydrogen in body-centered cubic (bcc) metals such as pure iron is found to be the primary cause of hydrogen embrittlement, in contrast little is known about this interaction in face-centered cubic (fcc) metals such as stainless steel. In present study, hydrogen spectra evolved from 316L and 304 stainless steels during elastic and plastic deformation were detected using a quadrupole mass spectrometer. For 316L stainless steel, hydrogen desorption increased rapidly when plastic deformation began, since the dislocation dragged hydrogen to the surface of the specimen. In contrast, hydrogen desorption increased with applying strain for 304 stainless steel, because of phase transformation from austenite into martensite with larger hydrogen diffusivity. And the amount of desorbed hydrogen increased with decreasing strain rate. These results indicate that dislocation can drag and transport large amounts of hydrogen when the dislocation velocity approaches the hydrogen diffusion rate. These findings lead to the conclusion that an interaction between dislocation and hydrogen occurs in not only bcc but also in fcc metals.