TiVZrNb Multi-Principal-Element Alloy: Synthesis Optimization, Structural, and Hydrogen Sorption Properties.

Area of Science:

• Materials Science
• Hydrogen Storage Technologies
• Alloy Development

Background:

• Multi-principal-element alloys (MPEAs) are increasingly explored for solid-state hydrogen storage.
• Research has primarily focused on mechanical and microstructural properties, with less attention on hydrogen sorption.

Purpose of the Study:

• To optimize the synthesis and evaluate the hydrogen storage properties of the MPEA Ti0.325V0.275Zr0.125Nb0.275.
• To compare hydrogen desorption characteristics of MPEAs synthesized via different methods.

Main Methods:

• Synthesis by high-temperature arc melting and ball milling under Argon.
• Characterization of phase structure and hydrogen sorption properties.
• Theoretical investigation using random distribution and first-principle calculations.

Main Results:

• The MPEA crystallizes into a single-phase body-centered cubic (bcc) structure.
• Maximum hydrogen uptake reached 1.7 H/M (2.5 wt%), with a transition to a body-centered tetragonal (bct) dihydride phase.
• Reactive ball milling under hydrogen pressure directly formed the bct dihydride phase.
• The material produced by reactive ball milling exhibited the best hydrogen sorption, stabilizing at approximately 2 wt% reversible capacity after initial cycling.

Conclusions:

• Reactive ball milling is a promising method for synthesizing MPEAs with enhanced hydrogen storage capabilities.
• The MPEA Ti0.325V0.275Zr0.125Nb0.275 demonstrates potential as a solid-state hydrogen storage material.
• Theoretical calculations can complement experimental findings in predicting hydride stability.