High pressure study and electronic structure of NiAl and Ni₃Al compounds

Nickel aluminide intermetallic compounds, mainly NiAl and Ni₃Al, have been considered as promising high-temperature structural materials because of their high melting points, low densities and good oxidation resistance. Ni-Al intermetallics are potential candidates as heat shields in chambers and gas turbines, however, these materials suffer from brittleness. The Thermodynamic properties with advance first-principles approach where predicting the structural and physicals properties of the NiAl and Ni3Al compounds. This study presents the room temperature crystallographic, metallurgical, and electronic properties of the Ni₃Al and NiAl compound, as a function of pressure. Both x-ray diffraction (XRD) measurements and full potential linearized augmented plane wave (LAPW) calculations were applied. No phase transition was observed in the XRD measurements up to a pressure of ∼30 GPa. The Holzapfel equation was used to fit the volume-pressure curve to the equation-of-state. The bulk modulus (B₀) at ambient pressure was calculated from the X-Ray data, sound-velocity and density measurements, and from the LAPW calculations.