Microstructural study on the slope of plateau pressure in TiFe0.8Al0.2 hydrogen storage alloy

In the TiFe0.8Al0.2 alloy, the Ti2Fe phase was precipitated, and the B2 phase was separated into two B2 phases. The alloy absorbed hydrogen at room temperature without any thermal activation process by forming the Ti2Fe phase. The hydrogen absorption and desorption behaviors were examined, and the slope of the plateau pressure was severely formed. The two B2 phases had different compositions. The hydride-forming enthalpies of the two B2 phases were calculated through a density function theory calculation, and the values of the two B2 phases were different. Therefore, it was confirmed that the slope of the plateau pressure was severely formed because of the separation of the B2 phase.