Positron annihilation study of palladium-deuterium system

Positron lifetime and Doppler broadened lineshape measurements are reported in deuterium charged Pd. Marked increase and saturation in annihilation parameters in the concentration range of 0.02 < D/Pd < 0.67 are explained by the increase of dislocation density arising from the build-up of deuteride (β) precipitates in the ∝ - phase and eventual transformation of the mixed phase to the β -phase. A comparison is made with measurements on H-charged Pd. Isochronal annealing results of Pd, after 40% cold work and deuteration to β -phase, indicates the dissolution of the β -phase at 473K, confirmed by the simultaneous weight loss measurements. A plateau observed in the recovery between 473 and 673K is explained by the interaction of dissolved deuterium with dislocations and this seems to shift the dislocation recovery to higher temperature