Influence of annealing on microstructure and hydrogen storage properties of V48Fe12Ti15Cr25 alloy

V48Fe12Ti15Cr25 alloy was prepared using vacuum arc melting and was subsequently annealed for 10 h at 1273 K. The effects of annealing on the hydrogen storage properties and microstructure of the V48Fe12Ti15Cr25 alloys were investigated. The results indicated that the alloy consisted of main body-centered cubic, Ti-rich, and TiFe phases. After annealing, the kinetic properties of the alloy were improved but its hydrogen storage capacity was slightly reduced. The kinetic mechanisms of the hydrogen absorption and desorption of the alloys were studied. The dehydrogenation enthalpy of the alloy was decreased by 2.57 kJ/mol after annealing. Differential scanning calorimetry indicated that the hydride decomposition temperature of the annealed alloy was decreased. The hydrogen desorption activation energies of the as-cast and annealed alloys were calculated to be 79.41 and 71.25 kJ/mol, respectively. The results illustrated that annealing was a beneficial method of improving the kinetic and thermodynamic properties of the hydrogen absorption/desorption of the alloy.