The average dislocation velocity in hydrogenated single crystals was measured directly as a function of the resolved shear stress, at 293K, by using the etch-pit technique. It was found that the dislocation velocity in the presence of H was 5 to 25 times greater than that without H; for a given resolved shear stress. It was deduced that H decreased the activation energy for dislocation motion in these monocrystals. This appeared to be the first evidence of H-enhanced dislocation mobility in Ni3Al.

Hydrogen-Enhanced Dislocation Velocities in Ni3Al Single Crystals. Jiang, C.B., Patu, S., Lei, Q.Z., Shi, C.X.: Journal of Materials Research, 2000, 15[1], 7-9