Influence of dislocations on deuteride formation in single crystal palladium

The effect of dislocations on deuteride formation in the Pd-D system has been investigated with small-angle neutron scattering (SANS). Deuteride precipitation morphologies in well-annealed single crystal Pd and deformed single crystal Pd have been determined with SANS. High densities of dislocations were introduced into the deformed sample by cycling across the deuteride miscibility gap. The characteristic response from small, 20-30 Angstrom thick, plate-like particles has been observed in the SANS measurement of both sample types. We believe these small plates act as precursors to the formation of much larger, tens-of-microns thick incoherent plate-like particles. These much larger deuteride plates have a preferred habit plane that depends on sample type; (100) for the well-annealed matrix and (110) for the deformed matrix.