Single crystals, with suitably-oriented surfaces and tensile axes, were used to study the rate of H transport by dislocations (table 35). Concurrent trapping was suppressed, in most cases, by selecting easy-glide orientations. It was found that the H flux which was transported by dislocations qualitatively reflected dislocation egress from the crystal surface. From a quantitative point of view, the H transport-rate increased with decreasing strain-rate. Edge kinks appeared to have the greatest ability to transport H at the lowest strain-rate (1.6 x 10-8/s). A negligible effect of the lattice H content upon dislocation transport was found. This was attributed to the kinetic nature of this process, where equilibrium between the H concentrations at the dislocation and in the lattice was unlikely. A small effect of temperature upon the dislocation transport rate was also observed at temperatures of between 12 and 78C. This was consistent with the assumption that the thermal energy provided by a higher temperature was too small to affect the interaction between H and mobile dislocations.

Dislocation Transport of Hydrogen in Iron Single Crystals. C.Hwang, I.M.Bernstein: Acta Metallurgica, 1986, 34[6], 1001-10