Effect of Zr substitution for Ti on Ti19.5V40Mn16.2Cr9.8Ni14.5 alloy -: I:: Microstructure and hydrogen storage property

To improve the electrochemical performance of Ti-V-based hydrogen storage alloy of solid solution type, partial Ti in Ti19.5V40Mn16.2Cr9.8Ni14.5 alloy has been substituted by Zr. It's found by XRD and SEM that all the (Ti1-xZrx)(19.5)V40Mn16.2Cr9.8Ni14.5 (x=0, 0.1, 0.15, 0.2, 0.25, 0.3) alloys consist of Ti-V-based BCC phase and C14 Laves phase. With increase of Zr substitution, the content of C14 Laves phase increases and the Ti-V-based BCC phase turns from dendritic structure to an island structure enveloped by C14 Laves phase. The PCT curves indicate that the equilibrium pressure for hydrogen absorption/desorption depresses steadily due to the expansion of cell volume of C14 Laves phase and the hydrogen absorption/desorption capacity increases firstly and then decreases due to the increase of the content of C14 Laves phase with x from 0 to 0.3.