First-principles study of NiAl alloyed with Co

The site preference of Co in NiAl and its effects on structural, elastic, electronic and thermal properties were investigated by performing first principles calculations using density functional theory (DFT). The site preference was investigated by calculating the transfer energy of NiAl alloys with Co. The result shows that Co tends to occupy Ni site. By analyzing changes in electronic density of states, Mulliken population, overlap population and valence charge density, the electronic property and bond characters were discussed. The elastic properties calculation shows that Co increases alloy hardness. Moreover, the pressure and temperature dependences of the thermal expansion coefficient, bulk modulus, Debye temperature and heat capacity in a wide temperature (0-1600 K) and pressure (0-30 GPa) ranges are presented in this study.