Microstructures and hydrogen storage properties of LaNiFeVMn alloys

Multicomponent high entropy alloys based on LaNi5 phase are investigated as hydrogen storage materials. The multicomponent LaNiFeVMn alloys are produced from pre-alloyed and elemental gas-atomized powders using Laser Engineered Net Shaping (LENS) technology. The effect of the alloy chemical composition on the hydrogen storage properties are elucidated in terms of the structure, phase composition and alloy formation entropies. The results of phase analysis indicates that laser manufactured alloys possess primary two-phase structure that changes from σ + La(Ni,Mn)5 to FCC + La(Ni,Mn)5 alloys. Maximum hydrogen capacity of LaNiFeVMn alloys is proportional to the atomic content of lanthanum which is able to form CaCu5-type La(Ni,Mn)5 phase. Produced alloys show differential behavior while forming the hydride phase and no simple relationship between phase compositions and pressure-composition curves can be observed.