Effect of stoichiometry on hydrogen storage performance of Ti-Cr-VFe based alloys

In order to develop new alloys with high hydrogen storage capacity, commercially available VFe alloys were used to substitute partial Cr of TiCr1.8. In this paper, the effects of stoichiometry on hydrogen storage performance of pseudo-binary TiCr2X(VFe)X (X=0.3-0.9) alloys were investigated by X-ray diffraction (XRD) and pressure composition temperature (PCT) tests. XRD tests showed that body centered cubic (BCC) phase and Ti1.07Cr1.93 phase coexisted in these alloys. The crystal cell parameters of BCC phase decreased linearly with increasing ratio of (Cr+VFe)/Ti. The hydrogen storage capacity of these alloys changed nonlinearly with the increase of (Cr+VFe)/Ti. The alloys with slightly substoichiometric composition were more suitable for hydrogen storage.