Study of the mechanical and thermodynamic properties on NiAl and Ni_3Al

摘要

The stuctural, elastic and thermodynamic properties of B2-NiAl and L1_2-Ni_3Al intermetallic compounds are systemically investigated. Using a first principle pseudopotential plane-wave method, several basic mechanical parameters of B2-NiAl and L1_2-Ni_3Al crystals, such as the equilibrium volume, the bulk modulus, the elastic constants, the Zener anisotropy factor, the Poisson's ratio, the Young's modulus and isotropic shear modulus are firstly calculated. And then the temperature dependence of the equilibrium volume, the bulk modulus, the thermal expansion coefficient, the heat capacity, the Debye temperature and the Gruneisen parameter are further evaluated in the framework of a quasi-harmonic Debye model. Finally, a special attention is paied on the mutual influence of pressure and temperature on mechenical and thermodynanic properties of B2-NiAl and L1_2-Ni_3Al intermetallic compounds in the range of 0-20 GPa and 0-1000 K.