Characterization of Ti-based hydrogen absorbing alloys

In this paper, Ti-x wt.% Zr (x = 25, 30, 35) alloys were developed and their hydrogen absorption properties were characterized systematically. Phase structure investigation indicates that experimental Ti-x wt.% Zr (x = 25, 30, 35) alloys are solid solutions with HCP (hexagonal close-packed) structure. And the X-ray diffraction patterns of hydrided alloys showed that the main phase composition is FCC (face-centered cubic) structure, the minority FCC Ti2ZrH4 phase was also observed in hydrided Ti-30 wt.% Zr alloy. Besides, the hydrogen absorption thermodynamic and kinetic properties were characterized, thermodynamic calculation was combined with experiments for the first time, thermodynamic model of the Ti–Zr–H ternary system was developed by using first-principles calculations combined with CALPHAD (CALculation of PHase Diagrams) method, the predicted PCT curves agree well with experimental data. Properties of Ti-x wt.% Zr (x = 0–50) alloys at 573 K were also predicted.