Small-angle neutron scattering measurements were used to investigate deuteride particle morphology and phase transformation temperature hysteresis in low-concentration Nb-D alloys. It was noted that deformation by cold rolling, and/or by previous deuteride cycling, produced a coarse deuteride particle distribution. This was attributed to a more heterogeneous precipitation process which was aided by dislocations. Deuteride precipitation in deformed samples was observed immediately upon crossing the incoherent solvus line during temperature reduction, and was consistent with dislocation-aided nucleation. Deuteride dissolution was observed at the initial onset of heating, in cold-rolled material. This was attributed to the availability of elastic accommodation energy for deuteride particles, embedded in the severely work-hardened host matrix. That is, the elastic energy assisted dissolution.

Effect of Lattice Defects and Temperature Transition Rates on the Deuteride (Hydride) Particle Morphology and Phase Transformation Thermal Hysteresis in Niobium. B.J.Heuser, W.C.Chen: Journal of Physics - Condensed Matter, 1999, 11[38], 7195-210