Phase equilibria in the Mg–Ti–Ni system at 500 °C and hydrogenation properties of selected alloys

A number of ternary Mg–Ti–Ni alloys have been synthesized by high energy ball milling, followed by annealing heat treatment. On the basis of X-ray phase analysis of these alloys an isothermal section of the Mg–Ti–Ni phase diagram at 500 °C has been constructed. One ternary intermetallic compound with Mg3TiNi2 stoichiometry that adopts an ordered Ti2Ni-type structure has been identified. Binary cubic TiNi compound dissolves considerable amount of Mg to form a ternary phase MgxTi1−2/3xNi1−1/3x crystallizing in the CsCl-type structure and existing over the range of compositions 0 < x ≤ 0.5. Other binary phases do not show appreciable solubility of the third component. The hydrogenation behavior of Mg3TiNi2 compound and Mg0.5Ti0.67Ni0.83 solid solution phase has been studied.