First-principles studies of Ni–Ta intermetallic compounds

The structural properties, heats of formation, elastic properties, and electronic structures of Ni–Ta intermetallic compounds are investigated in detail based on density functional theory. Our results indicate that all Ni–Ta intermetallic compounds calculated here are mechanically stable except for P21/m-Ni3Ta and hc-NiTa2. Furthermore, we found that Pmmn-Ni3Ta is the ground state stable phase of Ni3Ta polymorphs. The polycrystalline elastic modulus has been deduced by using the Voigt–Reuss–Hill approximation. All Ni–Ta intermetallic compounds in our study, except for NiTa, are ductile materials by corresponding G/K values and poisson's ratio. The calculated heats of formation demonstrated that Ni2Ta are thermodynamically unstable. Our results also indicated that all Ni–Ta intermetallic compounds analyzed here are conductors. The density of state demonstrated the structure stability increases with the Ta concentration. - Graphical abstract: Mechanical properties and formation heats of Ni–Ta intermetallic compounds are discussed in detail in this paper. Highlights: ► Ni–Ta intermetallic compounds are investigated by first principle calculations. ► P21/m-Ni3Ta and hc-NiTa2 are mechanically unstable phases. ► Pmmn-Ni3Ta is ground stable phase of Ni3Ta polymorphs. ► All Ni–Ta intermetallic compounds are conducting materials.