Investigation of the microstructure, crystal structure and hydrogenation kinetics of Ti-V-Cr alloy with Zr addition

The effect of 4 wt% Zr as additive in Ti_xV_70-xCr₃₀ (x = 10 to 50) alloy has been investigated. After casting, all of these alloys were multiphase but with different microstructure and phase composition. From X-ray diffraction, bcc structure of all as-cast alloys was confirmed. For alloys x = 30 and 40, a Ti and a Ti-Zr high pressure-high temperature phase were observed along with the bcc phase. Upon hydrogenation, bcc phase transformed to a body centred tetragonal and a face centred cubic phase. Only alloy x = 40, has shown a complete hydrogenation. For x = 20 and 30, a bct phase was seen along with the bcc and fcc phase. The first hydrogenation kinetics of Zr added alloys were found to be faster than without additive but not as fast as with 7Zr + 10 Ni additive. It was also found that the volume taken by the hydrogen atom in the fcc phase decreases with increasing value of the bcc lattice parameter.