The niobium–hydrogen system – an electron microscope study. II. Low-temperature structures

The structure and morphology of low temperature hydride phases is investigated. Quenching of dilute alloys produces small hydride particles which emitted interstitial dislocation loops into the matrix. Irreversible dislocation “skeletons” were generated when such hydride precipitates were thermally dissolved. Three ordered solutions where observed: the β-phase above −45 °C the ζ-phase from −45 to −65 °C, and the ϵ-phase below −65 °C. The reciprocal lattices of ζ and ϵ were determined. The ϵ-phase is identical with the hydride Nb4D3 found by Somenkov et al. ζ and ϵ are orthorhombic with the same lattice parameters as β.