Blocking of hydrogen-dislocation interactions in palladium by interstitial carbon (boron) solutes

It has been shown that the segregation of hydrogen to dislocations at 323 K decreases markedly in palladium doped with interstitital carbon or boron after a relatively low temperature annealing, 423 K. By contrast, after a similar treatment, pure palladium continues to show a large segregation of hydrogen to dislocations. TEM studies have shown, however, that the dislocation densities are large in both the pure palladium and the carbon doped samples after annealing at 423 K. These results are consistent with the explanation that the heavy interstitial atoms, carbon or boron, migrate to dislocations at 423 K and block these dislocations for occupation by hydrogen.