A first-principles calculation of structural, mechanical, thermodynamic and electronic properties of binary Ni-Y compounds

The intermetallic compounds between rare earth (RE) elements and transition metal elements have been comprehensively researched due to their appealing magnetic, electronic, optical and thermal properties, in which Ni-Y alloys are one kind of important system. In this work, a systematic investigation concerned with structures, elastic, and thermodynamic properties of Ni17Y2, Ni5Y, Ni7Y2, Ni3Y, Ni2Y, NiY, Ni2Y3 and NiY3 in Ni-Y systems is implemented by means of first-principles calculations. NiY has the lowest formation enthalpy within -0.49 kJ per mol per atom. Ni5Y has the largest bulk modulus, shear modulus and Young's modulus of 181.71 GPa, 79.75 GPa and 208.70 GPa, respectively. Furthermore, the effects of different concentrations of yttrium on the mechanical and thermal properties of Ni-Y compounds are estimated by using the Voigt-Reuss method. The electronic density of states and chemical bonding between Ni and Y are key factors that determine mechanical and thermodynamic properties of these compounds. What's more, results indicate that all compounds are dynamically stable as shown by the calculated phonon dispersions.