Abstract: The effect of Nb on hydrogen storage properties of TiV_0.9Cr_1.3 alloy was nvestigated. It was found that all alloys were single phases with BCC structures and dendritic crystals, in which minor Laves（Cr₂Nb）phase were observed and the second dendritic crystals disappear ( x＞0.3). As x increases from 0 to 0.4，the lattice parameters increase and the maximum hydrogen storage capacities, efficient hydrogen storage capacities and the desorption plateau pressure of the alloys decrease, while flatness of the desorption plateau region is improved. Slope of the desorption plateau region decreases from 1.59 to 0.71. The absolute value of enthalpy and entropy for hydrides increase. The TiV_0.6Cr_1.3Nb_0.3 alloy exhibits the maximum hydrogen storage capacities of 3.254%,the efficient hydrogen capacity of 2.367%, desorption plateau pressure of 0.09 MPa and slope of the desorption plateau region of 1.0.

Key words: desorption plateau slope
, hydrogen storage capacities, phase structure, Ti-V-Cr-Nb alloy