Microstructure and hydrogen storage properties of V40Ti20Cr32Fe8 alloy by heat treatment

Abstract

The microstructure, crystal structure, hydrogen storage properties and thermal stabilities of as-cast and annealed V40Ti20Cr32Fe8 alloy prepared by arc-melting were studied in this work. It was confirmed that both as-cast and annealed (973 K/72 hrs) V40Ti20Cr32Fe8 alloys are body-centered cubic (bcc) main phase and C14-typed Laves secondary (Cr2Ti). Experimetnal results show that the maximum hydrogen absorption capacities of as-cast V40Ti20Cr32Fe8 alloy at 303 K, 333 K and 363 K are about 2.25 wt.%, 1.75 wt.% and 1.12 wt.%, while that of the annealed alloy at 303 K, 333 K and 363 K are about 2.26 wt.%, 1.76 wt.% and 1.26 wt.%, respectively. The maximum hydrogen desorption capacities of as-cast V40Ti20Cr32Fe8 alloy at 303 K, 333 K and 363 K are about 1.15 wt.%, 0.89 wt.% and 0.60 wt.%, while that of the annealed alloy at 303 K, 333 K and 363 K are about 1.22 wt.%, 0.90 wt.% and 0.61 wt.%, respectively. It is indicated that hydrogen absorption/desorption kinetics of the V-Ti-Cr-Fe alloy is greatly improved by heat treatment.