On the amorphization behavior and hydrogenation performance of high-energy ball-milled Mg2Ni alloys

•Amorphous Mg2Ni has been obtained by high energy ball milling the as-cast alloy.•The amorphization behavior of polycrystalline Mg2Ni is presented.•The crystallization behavior of the amorphous Mg2Ni alloy is illustrated.•Establish the relationship of milling, microstructure and hydrogenation properties.

Amorphous Mg2Ni alloy was prepared by high energy ball-milling starting with polycrystalline Mg2Ni which was prepared with the help of a metallurgy method by using a SPEX 8000D mill. The microstructural and phase structure characterization of the prepared materials was performed via scanning electron microscopy, transition electron microscope and X-ray diffraction. The thermal stabilities were investigated by differential scanning calorimetry. The apparent activation energies were determined by means of the Kissinger method. The first and second crystallization reactions take place at ~ 255 °C and ~ 410 °C, and the corresponding activation energy of crystallization is Ea1 = 276.9 and Ea2 = 382.4 kJ/mol, respectively. At 3 MPa hydrogen pressure and 250 °C, the hydrogen absorption capacities of crystalline, partially and fully amorphous Mg2Ni alloy are 2.0 wt.%, 3.2 wt.% and 3.5 wt.% within 30 min, respectively.

Graphical AbstractWe mainly focus on the amorphization behavior of crystalline Mg2Ni alloy in the high energy ball-milling process and the crystallization behavior of the amorphous Mg2Ni alloy in a follow-up heating process. The relationship of milling, microstructure and hydrogenation properties is established and explained by models.Figure optionsDownload full-size imageDownload as PowerPoint slide