Structural, microstructural and hydrogenation characteristics of Ti-V-Cr alloy with Zr-Ni addition

In this paper we report the effect of Ti-proportion and addition of Zr-Ni on the crystal structure, morphology and hydrogen storage kinetics of Ti-V-Cr alloy. For this study, five alloys of compositions Ti_xV_70-xCr₃₀ (x = 10, 20, 30, 40, 50) added with 4 wt% of 7Zr+10Ni were synthesized. Scanning electron microscopy revealed that all alloys were multiphase. X-ray powder diffraction confirmed that all the as-cast alloys have the body-centred cubic (bcc) phase as the main phase. The same amount of (7Zr+10Ni) was added in all of the alloys, but each alloy has shown a different elemental concentration in their secondary phases. For alloys x = 10 and 20, a Zr rich secondary phase was formed but for alloys x = 30, 40 and 50, the secondary phase has relatively high concentration of all elements. Upon hydrogenation, the bcc phase transformed into a face-centred cubic (fcc) phase. For x = 20, 30 and 40 a body-centred tetragonal (bct) phase was also observed along with fcc phase. Hydrogenation kinetics of all of these alloys was measured and it was found that absorption capacity increased with Ti-content. The maximum absorption capacity of 3.6 wt% was achieved for x = 50.