Multi-Functional Properties of Superconducting and Hydrogen Storage in TaNb2HfZrTi High Entropy Alloy

Abstract

Metallic hydrogen storage and robust mechanical properties in superconductors may have critical importance in superconducting applications with liquid hydrogen cooling agent. Here, we investigate the superconducting and hydrogen storage functionalities in bulk TaNb2HfZrTi high-entropy alloys (HEAs) synthesized by mechanical alloying followed by hot-press sintering. The optimized superconducting sample (HP-900) exhibits a sharp superconducting transition at T c = 7.8 K, a high upper critical field mu 0 H c2(0) = 10.85 T, and a critical current density exceeding 2.9 x 105 A cm- 2 at 4 K, surpassing values reported for arc-melted and spark-plasma-sintered counterparts. Meanwhile, the HEA sample achieves an outstanding room-temperature hydrogen storage capacity (H/M = 2.23, 3.8 wt.% at 20 degrees C, 100 bar), which is high value corresponding to the state-of-the-art metallic high entropy alloy hydrides at room temperature. This unique integration of bulk processing, microstructural control, and dual functional performances establishes that the TaNb2HfZrTi can be a benchmark platform for multifunctional BCC high-entropy alloys, and it provides design principles for next-generation cryogenic and solid-state hydrogen technologies.