High-entropy alloys (HEAs) have attracted considerable attention due to their unique properties such as high strength, hardness, and corrosion resistance. In recent years, HEAs have also been investigated as promising hydrogen storage materials. This paper presents a study of a high-entropy Al–Cu–Fe–Ni–Ti alloy synthesized by vacuum arc melting to evaluate its potential as a solid hydrogen storage material.
The resulting alloy is characterized by a microstructure consisting of several phases, which is typical for SHE. X-ray phase analysis showed the presence of face-centered cubic (FCC) and body-centered cubic (BCC) phases. The microhardness of the alloy was 450 HV, which indicates its high strength.
The hydrogen sorption study was conducted using the temperature-programmed desorption (TPD) method. The alloy demonstrates the ability to reversibly absorb hydrogen at cryogenic temperatures. The maximum hydrogen content in the alloy was 1.2 wt.%. The hydrogen desorption temperature is in the range from 100 to 200 °C, which is acceptable for practical use.
In this paper, the production processes, structural features, microstructure and hydrogen storage characteristics of single-phase cubic high-entropy Al–Cu–Fe–Ni–Ti alloys were investigated. The alloy was produced using a high-energy ball mill in a hexane environment, which was used to control the grinding process. X-ray diffraction analysis showed that the obtained alloy is a single-phase high-entropy material with a crystal lattice parameter of 0.289 nm.
The experimental results demonstrate that the high-entropy Al–Cu–Fe–Ni–Ti alloy exhibits excellent hydrogen absorption kinetics, reaching 2.3 wt.% in 4 minutes at 300 °C and 50 atm hydrogen pressure. Hydrogen desorption is about 1 wt.% in 3 minutes under the same conditions. After 25 hydrogen storage cycles, the reversible capacity remained virtually unchanged, decreasing by only 0.1 wt.%.
The proposed approach to the creation of high-entropy alloys provides valuable information for the development of new materials intended for hydrogen storage.
The results of the study show that the high-entropy Al–Cu–Fe–Ni–Ti alloy is a promising material for storing solid hydrogen. Further studies are aimed at optimizing the alloy composition and improving its sorption characteristics.
Author: Yogesh Kumar Yadav, Mohammad Abu Shaz, Thakur Prasad Yadav
Institute:
Department of Physics, Institute of Sciences, Banaras University, Varanasi, 221005, Uttar Pradesh, India
Department of Physics, Faculty of Science, University of Allahabad, Prayagraj, 211002, Uttar Pradesh, India