Alloying element additions to Ni ₃Al: Site preferences and effects on elastic properties from first-principles calculations

First-principles calculations were performed to study the effects of alloying elements (Mo, Re, Ta, W, Ti, Co, Nb, Ru, Cr, Y) on the elastic properties of Ni ₃Al. The site preferences of the alloying elements in Ni3Al at different temperature and concentrations were predicted. The influence of alloying elements on the lattice parameters of Ni ₃Al were calculated and compared with the values fitted from experimental data. The effects of alloying elements on the elastic constants of Ni ₃Al were present. The directional shear and Young's moduli for single-crystal Ni ₃Al alloys with alloying elements were estimated. The bulk, shear, and Young's moduli of polycrystalline alloys were obtained. It is found that all the alloying elements occupy Al sites except Ru and Co, which may occupy both sites depending on concentration and temperature. All the elements increase shear and Young's moduli of single-crystal Ni ₃Al in all orientations except Cr, Co and Y. All the elements increase both bulk and shear moduli of polycrystalline Ni ₃Al except Co and Y. The solute atoms with higher bulk modulus tend higher bulk modulus of Ni ₃Al alloys, and the bulk modulus is related to the mole volume either.