Microstructure evaluations and hydrogenation properties on Ti–xNb–10Cr alloys

Ti–Cr alloys consist of BCC solid solution, C36, C14, C15 Laves phase at high temperature. Among others, the BCC solid solution phase was reported to have a high hydrogen storage capacity. However, activation, wide range of hysteresis at hydrogenation/dehydrogenation, and degradation of hydrogen capacity due to hydriding/dehydriding cycles must be improved for its application. In this study, to improve such problems, we added a Nb. For attaining target material, Ti–1Nb–10Cr, Ti–3Nb–10Cr and Ti–5Nb–10Cr specimens were prepared by a planetary ball mill. The milling process was carried out under a high pressure nitrogen atmosphere. Specimens synthesized were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and thermogravimetric analysis/differential scanning calorimetry (TG/DSC). In order to examine hydrogenation behavior, a pressure-composition-isotherm (PCI) was performed at 323, 373, 423, 473 and 523 K.