An ab initio investigation of the effect of alloying elements on the elastic properties and magnetic behavior of Ni₃Al

First principles density functional theory calculations were performed on pure and doped Ni₃Al. The dopants investigated were Cr, Zr, La and Ce at concentrations of 3.13, 6.25 and 9.38 at.%, and B was considered at concentrations of 3.03, 5.88 and 8.57 at.%. The defect formation energies, doping site preferences, and elastic properties of pure and doped Ni₃Al were determined and compared to published theoretical and experimental results. The magnetic properties of Ni₃Al and, where appropriate, the dopants, were always taken into account, as the elastic constants predicted from spin-polarized and non-spin-polarized calculations were significantly different. The results were successfully correlated to the electronic structure through the electronic density using Miedema's established model (Miedema et al., 1973). The calculations revealed that Cr doping increases the bulk modulus of Ni₃Al and that all the other dopants considered decrease it.