Hydrogenation-Dehydrogenation Preparation of TiZrNbTa Refractory High-Entropy Alloy Powder

• • Optimal hydrogenation at 550 °C, 0.25 MPa H2 for 2 h yields hydride powder with D50 = 11.13 μm, H = 1.823%, O = 0.111%, enabling efficient mechanical crushing due to hydrogen embrittlement. • • Vacuum dehydrogenation at 450 °C for 1.5 h reduces hydrogen to 0.028% while limiting oxygen increase to 0.121%, achieving single-phase BCC structure essential for mechanical properties. • • The HDH process reduces average particle size from 11.13 μm to 5.67 μm, narrowing size distribution, which enhances sintering activity and densification in powder metallurgy. • • The process achieves low oxygen contamination (0.121%) compared to mechanical alloying or gas atomization, critical for preserving ductility and energy release performance in structural applications.