Influence of annealing treatment on the microstructure and hydrogen storage performance of Ti1.02Cr1.1Mn0.3Fe0.6 alloy for hybrid hydrogen storage application

Abstract

The as-cast Ti1.02Cr1.1Mn0.3Fe0.6 alloy for hybrid hydrogen storage vessel application was annealed at different temperatures (873K, 973K, 1123K, 1173K) for 2h, and annealed at 1123K for different time (2, 5, 8h) respectively, and their microstructure and hydrogen storage properties were investigated systematically. The results show that the as-cast alloy has a single C14 Laves phase, and all annealed alloys consist of a C14 Laves main phase and a secondary phase. After annealing at different temperatures for 2h, the hydrogen absorption pressure at 298K decreases, however, the maximum hydrogen storage capacity and desorption pressures at 318K decrease slightly too. As the annealing time extends, the hydrogen absorption plateau pressure at 298K and hydrogen desorption plateau pressure at 318K increase, and the hydrogen desorption capacity increases first and then decreases, which reaches the highest desorption capacity of 1.721wt.% at the annealing time of 5h. Among the studied alloys, the alloy annealed at 1123K for 5h has the best overall properties for hybrid hydrogen storage application, its hydrogen absorption plateau at 298K is 29.09MPa, its hydrogen desorption plateau pressure at 318K is 45.12MPa, its hydrogen storage capacity is 1.721wt.% and its dissociation enthalpy (ΔHd) is 17.78kJ/mol H2.