| Summary: | TiVNbTa refractory high-entropy alloy was prepared by vacuum electromagnetic levitation melting technology.The hydrogen absorption and desorption properties of the alloy were tested by multi-channel hydrogen storage tester, the hydrogen absorption-desorption behavior and corresponding kinetic mechanisms were investigated.The results show that BCC single-phase structure in the alloy is transformed into three new phases including TiH1.971, Nb0.696V0.304H and Nb0.498V0.502H2 after the hydrogen absorption process. The hydrides in the hydrogenated high-entropy alloy decompose at 519, 593 K and 640 K, respectively and change to BCC phase again after hydrogen desorption process.Therefore, the hydrogenation reaction is reversible.The alloy exhibits high hydrogenation (dehydrogenation) rates at 423-723 K. The kinetics of hydrogen absorption and desorption can be described by Johnson-Mehl-Avrami (JMA) model and second-order rate model, respectively. The apparent activation energies Ea of hydrogen absorption and desorption are -21.87 J/mol and 8.67 J/mol, respectively.
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