Trapping and Transport of Hydrogen by Plastic Deformation in Iron

Hydrogen permeation is studied under the condition of tension with a GYF-1⁽¹⁾ slow strain rate testing (SSRT) machine. Study of the action of dislocations in hydrogen permeation indicates that the action of dislocations relates to the (1) tension state, (2) initial conditions, and (3) boundary conditions of the experiments. The action of dislocations on hydrogen permeation is different from that of dislocations during hydrogen evolution because of the difference of the initial state. The dislocation created by tension reduces the permeation current. The created dislocation increases the rate of hydrogen evolution. When charging is continued under the different boundary conditions, dislocations reduce hydrogen flux; when charging is stopped, dislocations enhance the rate of hydrogen evolution. The different action of dislocations can be explained by the idea that a dislocation is a reversible trap.