## 1 Introduction  
Body Centred Cubic (BCC) Vanadium-based alloys have been studied intensively since [PERSON] et al. reported that vanadium hydride can store 3.8 wt % of hydrogen (i.e., dihydro \(\mathrm{VH}_{2}\)) and has a reversible capacity of about 2 wt % [1; 2; 3]. For hydrogen storage applications, one limitation of these alloys is the high price of vanadium. Thus, a low-cost alloy (i.e., with lower vanadium content) could be more attractive for industrial production. Following this idea, the effect of the addition of other transition elements has been studied by many groups [4; 5; 6; 7; 8; 9; 10; 11; 12]. In general, upon substitution, the reversible storage capacity decreases, but for most cases, the hydrogen capacity is around 2 wt %, which is acceptable for some applications.  
Metal hydrides containing vanadium may be too expensive to be commercially viable. One way to reduce cost is then to replace vanadium by the less expensive ferrovanadium [9; 11; 13; 14; 15; 16; 17; 18; 19]. For example, [PERSON] et al. found that the alloy TiCr\({}_{1.2}\)(FeV)\({}_{0.6}\) has a total hydrogen capacity of 3.0 wt % and a reversible capacity of 1.8 wt % [9]. [PERSON] et al. showed that the as-cast Ti\({}_{0.85}\)Zr\({}_{0.13}\)(FeV)\({}_{0.56}\)Mn\({}_{1.47}\)Ni\({}_{0.05}\) alloys was made of a C14 Laves phase and the FeO phase. The origin of the FeO phase was the replacement of V by FeV. However, annealing at 1000 \({}^{\circ}\)C for one hour resulted in a single phase with C14 Laves phase with a reversible hydrogen capacity of 1.6 wt %. [PERSON] et al. reported that the alloys TiMn\({}_{0.9}\)(FeV)\({}_{1.1}\) and TiMn\({}_{1.1}\)(FeV)\({}_{0.9}\) have faster activation kinetics than their pure vanadium counterpart [16]. The total hydrogen capacity was lower for the ferrovanadium containing alloys,but the reversible capacity was higher due to the modification of the plateau pressures. Recently, [PERSON] et al. synthesized (FeV80)\({}_{48}\)Ti\({}_{26}\)Cr\({}_{26}\) by the hydride powder sintering method [11]. They found that the hydrogen capacity was reduced when compared to the melted alloy. However, adding 4 at% of Ti the sintered sample was shown to have similar hydrogen absorption-desorption capacities than the melted sample. [PERSON] et al. studied TiZrMn BCC alloy for metal hydride actuators [19]. They showed that ferrovanadium could be used for cost reduction and that the Al impurity in ferrovanadium could reduce the hysteresis factor.  
Recently, we reported the investigation of Ti\({}_{1.56}\)V\({}_{0.36}\)Cr\({}_{1.08}\) Cr and Ti\({}_{1.26}\)V\({}_{0.63}\)Cr\({}_{1.11}\) alloys, to which Zr\({}_{7}\)Ni\({}_{10}\) was added to enhance the activation process [20; 21]. In order to decrease the cost of these alloys, we investigated the partial replacement of vanadium by ferrovanadium (FeV). For both alloys 50 at%, vanadium was replaced by ferrovanadium thus obtaining Ti\({}_{1.56}\)V\({}_{0.18}\)(FeV)\({}_{0.18}\)Cr\({}_{1.08}\) and Ti\({}_{1.26}\)V\({}_{0.315}\)(FeV)\({}_{0.315}\)Cr\({}_{1.11}\) alloys. The effects of partial replacement of V by FeV in these Ti-V-Cr alloys on the crystal structure, microstructure, and thermodynamics parameters are presented here.