Investigation on Ti0.94Zr0.08Cr1.0Mn0.6−xFe0.4+x (x = 0, 0.1, 0.2, 0.3, 0.4) Alloys for 25 MPa Hydrogen Compression Materials

For hydrogen refueling stations, metal hydride compressors offer a safe and efficient alternative to mechanical systems. This work systematically investigates Ti0.94Zr0.08Cr1.0Mn0.6−xFe0.4+x (x = 0, 0.1, 0.2, 0.3, 0.4) alloys for primary hydrogen compression targeting 25 MPa. All alloys crystallize as a single C14 Laves phase, with Fe substitution causing negligible lattice changes but leading to linearly increased particle size due to solid-solution strengthening. In the testing temperature range of −80 to −50 °C, the hydrogen storage capacity decreases with increasing Fe, whereas the effective desorption capacity improves. Pressure–composition isotherms exhibit single plateaus with elevated plateau pressures at higher Fe/Mn ratios. In the range of x = 0–0.4, the enthalpy of desorption decreases in magnitude with Fe content. Using Van’t Hoff extrapolations to 30 °C absorption and 80 °C desorption, the compression factor shows a non-monotonic trend, reaching a maximum of 1.99 at x = 0.2. This composition provides nearly a two-fold pressure boost, demonstrating promise for low-grade heat driven hydrogen compression in refueling infrastructure.